I don't want to get too bulky so Should I gain 15 more lbs??

It's only too bulky if shirt sleeves are tight. Better to be bulkier at 6'1" than skinnier. As for being an athlete, it's good as long as you don't brag about it or use it to pick up.

If you're 6'1.5 you should weight at least 200. It should be fine as long as it isn't pure fat.