We are early 30's so not too old.
I still wear a lettered hoodie all the time around the house and for casual errands sometimes, but other than that I don't have like a full wardrobe of stuff like in college.
I think one lettered tee will be fine, and then 2-3 non-clothing items. My alum chapter did spirit wear recently that we could order that said "Org Name Alumna" but that is closed now (it was a few months ago). I would have done that for her if the timing had lined up!
Edit: also I may be a little overzealous/excited about doing this because in college I never got to take a little and I'm considered her big, since I sponsored her, in terms of AI.