Are the opinions of others causing you to put too much pressure on yourself? I believe there are several examples in your post of others laying significant expectations on you. You are expected to...

• Achieve the great future predicted for you when you were in high school
• Match the success of your brother
• Meet the career expectations of your parents and rest of family
• Match the perceived sophistication of your peers and friends
• Conform to the social norm that you should have already finished the degree you want

Heavy burdens to bear. It’s thoughtful of you to consider the wishes of those around you, but are you allowing them to wield an unhealthy amount of influence?

I’ve recently begun to examine this issue in my own life. I’ve made some progress and it feels wonderfully liberating. Hope this helps.