Weight gain

Okay, so I’m about to start taking this weight gain powder. It’s like this big thing of powder, you can make into shakes. Currently I’m 5’4, weighing 111. I’ve been the exact same since middle school and here I am in college. No, I’m not gaining weight for anybody else, I’m doing it for myself. I’m wanting to get to at least 120 or 125, then I plan on to stop to taking it. My mom was exactly like me skinny for a while then gained tons of weight when she got pregnant and never lost it so she had to get weight loss surgery. My dad is skinny. Idk if I’m meant to be skinny like my dad or if I’m going to at some point blow up like my mom. But for right now I say I have a pretty fast metabolism. But for right now, If I was to start making these shakes and going to the gym will I get good results and look how I want? I might not even make it to 125, just whatever weight I feel like fits me, I’ll stop at. I refuse to do this without exercising.