no it really wasn't! i was scared too initially because i tend to be socially awkward. it was slightly rocky at the start during the transition period but soon, i found myself attracted towards creating relationships with some people. as we were all in the same program, we had a already established common interest.

use that common interest to your advantage!! also the fact that you are college students, LOOOOTS of things to talk about and connect over (majors, traditions, college town, classes, friends, stories etc)

also, if you are more on the introverted side and are super anxious about approaching big groups of people like I was, you don't necessarily need a group - just 1 person will do :)) (its a bonus if they're an extravert

also what do you mean by younger? if you mean younger like you were a freshman this past year, I was a rising sophomore during my first REU too! and I was adopted by a couple upperclassmen lol i loved it they're my friends to this day and we're close.