We've attended Aggieland Saturday several times with our older son, but think TAMUG might be a better fit for our HS freshman. I'm not nearly as familiar with that campus, though, and am hoping they have a similar event.
You could also see if there is a TAMUG summer Sea Camp of interest. That's s week on campus in the dorms doing marine related stuff.
My daughter did 5 different Sea Camps and enjoyed them all. She's now s freshman at TAMUG and enjoying it. They've made lots of campus improvements over the last 5 years or so. I'm a happy parent.
my daughter did the sea camps too and will be an incoming freshmen this fall at tamug, (her siblings are all at college station and are convinced she will switch) she said why, get all the football games at kyle with only having to deal with 20 kids in my classes