Former Gainer: Should I Gain More Fat, More Muscle, or Both?

Please read and give feedback VVVV

Hey people! I'm a former gainer that was on Youtube before. I don't intend to gain a whole lot of fat like I tried to do before. But, I would like to hear your opinions on what you think I should do with my body.

I was thinking of trying to gain more weight and have a wider, rounder waist,, or lose it and have a trimmer, more defined stomach. I do want to add more muscle to my frame though. Here, I just ate a really big dinner. I played tennis earlier today, but no weightlifting.

Other important things to know about me: I'm 15. I'm really short, lol. Only 5ft 2, 116 lb.