Right i wrote a massive post in here but somehow managed to delete it - Rockstar - considering you're a skinny lad like me, I'm guessing your metabolism is pretty fast.
Stay away from the gym - google "black monks isometrics", and you can do dips, pressups, squats and situps, and boxing, and swimming to get hench.
Isometrics are pure win - you can get strong as hell using these because you can fit them into a not so busy day, or do them over 2 days.
I do them every day, and unless my day is real busy, I find I can fit them all in in a day.
Considering your constitution/body type, hitting the gym hard i not a good idea - especially during the summer - the summer is the worst time, you wanna be chilling and swimming and doing isometrics - nothing much more than this unless you have a very slow metabolism and find it easy to get hench, then you can be a bit more vigorous.
Winter and spring are the best times for ANYONE to hit the exercise hard, and summer and autumn much less (although preparing for winter, autumn more exercise than summer).
A great investment is a big bulk bag of hemp seeds - thrown in the coffee grinder, they make a perfect addition for your protein shakes, as they have a ridiculous amount of protein in, and also all hte omega your body needs plus loads of healthy fats - superfood basically.
ANyone interested in getting stronger, faster - look up "food combining" - the science of food, I won't go into it more - that's up to you and how serious you are - but here you can change your diet a bit in order to be able to digest your food as efficiently as possible, and not give your body a hard time, producing excessive wastes.
Right that should be enough for now.
Peace