The comparison was between Indian love marriages, Indian arranged marriages, and American love marriages. Indian and American love marriages appear to be more similar to each other than either are to Indian love marriages in this respect... so unless you consider the American marriage age too young to make this decision, I'm not sure age is a factor.
Information that surprises you is interesting as it exposes where you have been miscalibrated, and allows you to correct for that.
I suspect the users of LessWrong have fairly similar beliefs, so it is probable that information that has surprised you would surprise others here, so it would be useful for them if you shared them.
Example: In a discussion with a friend recently I realised I had massively miscalibrated on the percentage of the UK population who shared my beliefs on certain subjects, in general the population was far more conservative than I had expected.
In retrospect I was assuming my own personal experience was more representative than it was, even when attempting to correct for that.