Is 23F and 20M a weird age gap?

Me (22F) and my boyfriend (20M) have been dating for about 5 months now. I am a first year graduate student and he is a junior at the same university. We met through mutual friends and the relationship has been really healthy and we both care a lot about each other. I just still have not been able to shake this feeling of insecurity and obsession over our age gap. Especially with me turning 23 in a month and him still being 20 for a few months after.

Our friends are overall supportive, but I’ve gotten judgmental comments from some friends and acquaintances and it really makes me uncomfortable and honestly angry.

Am I weird for dating someone 2.5 years younger than me? Why is our generation so judgmental and strange about things like this? I try not to care, and it’s not like someone else’s opinion would make me unhappy in our relationship. I’m just such a self conscious person and people’s reactions really do get to me. Is it normal for me to be so insecure obsessing over this age gap? Is there really a large maturity gap in ages like this? I know your early 20s are a time for development and figuring yourself out, but is it really that big a difference?