I've been trying to gain for a few years now. Since I was 16 I'm pretty sure. I weighed about 200lbs when I was 17. That's in the 99th centile. No idea what that means.
Honestly, trying to squeeze past tables with a big backside was difficult.
It was also clear that I was obese just from me sitting down. when I did sit down, my thighs just splayed out sideways and became basically twice as wide. Also had a lot of stretch marks then too.
But hey. There isn't any harm in gaining early on in life right?
9 months