i just have a quick questions. Ive been lifting for around 4 months and i grew from 163 to 181. 
Almost all of it it muscle but of course some fat has been added. How long should i gain for until i should cut. Is there an amount of time that you should bulk then cut or should it just be until you hit a certain amount of weight or bf%
This depends on your goals and height. If you gained 18 lbs to get to 181 and are 5’5 still lean, you might be satisfied with your look and can cut some bodyfat. If you are 6’1 and skinny fat and want to look like you even lift, 181 is not going to be big enough.
I’d say bulk to like 230-240 or so… then once you get your bloodwork back cut down to like 140.