Please pay no attention to that above post. If you want to put on weight you need to eat right, and junk won't get you there. Good genetics can't turn junk food into quality nutrition no matter how you slice it.
I would try to hit that 5k calorie mark daily and track your weight every MONTH. Not every day. Not every week. And make sure you weigh yourself in the exact same conditions every time, like morning with zero food in your stomach.
If you stick to the program for 3 months you will learn a lot about how your body reacts. But trial and error is the only way to really find out.
But trust me, about 3-5 years from now if you stay on track you are going to look fantastic regardless of weight. You will probably end up being a ripped 180-185lber.
You are already ahead of the game coming here and asking for advice at your age, and knowing what to eat. I had no clue at 20 what the hell I was doing. I was just starting to get it at 25.