At the start of the pandemic, I heard that Covid was likely to be a problem. I didn't pay much attention, because I remembered the Swine Flu "pandemic", and Covid was getting less attention than Swine Flu did at the time. I also knew that the media has a strong incentive to cause hype over things that aren't really dangerous trends. I am in an age range very unlikely to die from disease, and claims of a lung plague causing lasting brain problems sounded absurd.

I figured that if a disease about as deadly as the regular flu caused so much panic, and Covid caused less and mainly harmed people already at respiratory risk, I didn't need to worry about it.
I eventually updated my beliefs, but I don't see how I could have avoided making my mistake. How could I have done better?
Now that a bunch of answers are in, I will say what I think the mistakes were.
First of all, a clarification. I heard about it sometime in early February (I don't remember specifically since I wasn't paying much attention), and I re-examined the data and updated my belief in whether it was a problem at the beginning of March, when I noticed that even people who normally don't worry about things like this started considering a lockdown. Remember: I knew it was spreading, I thought that it wouldn't be much worse than regular diseases.
The mistake wasn't "I should have listened to the trustworthy sources instead of the untrustworthy ones". I didn't know much about which sources were the most reliable, and what I did know wouldn't have helped. For example, I know that where people put their own money is much more reliable than what they tell other people to do (why prediction markets are so much more accurate than other things). However, the US stock market reached an all time high on February 12, indicating that people whose whole job is paying attention to this stuff weren't worried at all.
The mistakes I did do were these:
- I had been too overconfident in civilization's ability to withstand plague. Disease has been pretty much eradicated, and even if a new one appears there are over-the-counter cough medicine and fever reducers and things.

My mistake was not re-evaluating this belief based on things that almost became big. I should have updated based on Ebola and SARS but didn't.
2. Personal experience said it was even less dangerous than the flu. My elderly great-aunt tested positive in late February, but was almost asymptomatic. Also, my parents and I got a bad cold at the end of January with the same symptoms (dry cough, fever, got better then a few days later it became bad again), and although we didn't think to test it at the time, once we heard of covid we thought that was probably it. Our symptoms definitely weren't worth freaking out about. I probably should have payed more attention to other people's reports of worse symptoms, although my prior of "lung virus causes permanent brain damage" was much less than "placebo effect and/or typical media terrible statistics", and although genetic variation is real it didn't seem likely to have "shut down the country" level severity. I'm not quite sure how this mistake could have been fixed.
3. I should have checked a source about China, not just from places that don't have much covid yet. I'm not fluent in Chinese, but I really should have at least checked how strictly they were quarantining and compared it to what they did during SARS. I didn't really look into it at all.
4. There was another problem, but this would take longer to explain and would need its own post.
Yes, any congressional report is political, but some are more purely political than others, which is why I pointed out that this one is produced by people all on one side of the aisle (which makes it likely to be more than averagely political) and considered how we might tell whether it's likely to be better than most things produced by people all on one side of the aisle (which it doesn't).
Your previous comment didn't look to me as if it was commenting on the level of political pressure, and to whatever extent it was it was therefore nonresponsive to its parent, which was commenting on whether in fact Dr Fauci did bad things, not on whether there is political pressure to admit/deny/insist/etc. that Dr Fauci did bad things.
Imaginary scenarios in which someone gives testimony before Congress that's damaging to Dr Fauci may be fun to imagine, but imaginary scenarios don't provide real evidence.
I can read the arguments in the report and evaluate them, but I can't so easily tell what arguments they aren't presenting because they don't lead the way they want, and I can't tell what evidence they aren't presenting because it points the wrong way, and I don't know how trustworthy the people they quote are, and if the report makes some claim about something that happened in China in 2019, or about alleged genetic evidence that SARS-CoV-2 is likely the result of engineering, then I can't readily tell whether that claim is true or false. So, alas, "just read the report and evaluate it for yourself" is a much less effective strategy than one might hope.
In any case, your great-grandparent comment didn't say "this report makes a strong argument, namely X". It just offered the report's conclusions as evidence:
I'm trying to understand whether there's actually any reason to think that this report's conclusions are any evidence of anything, or even that they're likely enough to be evidence that it's worth putting in the (substantial) effort it would take to tell whether the investigation and reporting are competent and honest, given that my prior for such things is that they are extremely unlikely to be so. I would expect a group composed entirely of Republican politicians to say Covid-19 was probably the result of a lab-leak of an artificial virus, and that China covered it up, and so forth, pretty much regardless of whether any of that is true, and pretty much regardless of the state of the evidence.
(I had a quick look at the report. It's 83 pages long and does indeed appeal to all sorts of alleged evidence I am not readily able to evaluate; my initial impression of its logic is not good; its authors seem to be excessively ready to jump from suggestive hand-waving to "so it is reasonable to conclude that ...". But I would expect it to be like that even if the conclusions are correct, because it is written by a partisan group of politicians and such groups are rarely very honest even when the claims they are making are true.)