I need to gain weight

Hi ! Sooo I need some advice from all my thick girls. I’m 16, 5’7 and about 105 pounds. My goal is to be at least 130 by July does anybody have any advice on healthy ways to gain weight or help increase calories intake? 😊 I’m super confident in my body I just feel like some days I’m not eating nearly enough and I feel underweight. I downloaded this app called MyFitnessPal but I can’t eat 2,000 calories if I get full from 200 😂 and I can’t buy apetmin** because I’m under age and my mom wouldn’t approve... plus I’m a little scared of the side effects

Here’s a visual representation of my size 😂