Am Sean Poland and I am 18 years old and I've been wanting to join to Marines.?

I would love and highly appreciate accurate feed back from a former Marine, current Marine, or anyone wise or educated in the ways of todays military, especially Marines which I prefer over the other branches. thorough feed back and help would be highly appreciated from me. I want to enter military law enforcement I believe and prefer Marine Corps but slightly considering not going because of professional swimming. Last I tried swimming was probably around 3 years ago and I was a very slow and weak swimmer who took twice as long to cross th under ground pool as everyon else at summer camp. I was wondering if anyone could fill me in who knows the true detailsof the Marines. I am not good at relaxing in deep water. will this b a problem in the Marines? I don't see myself as a very good floater if I can even float at all? The rest of boot camp I am not worried about because I have unshakable effort and determination and I have high adrenaline and high metabolism and do not se any reason why not join the marines except the swimming part is one thing I am uncertain of. What exactly must a marine endure over all involving water just to simply p the water tests with the minimum requirements? I must determine wether or not I can luck my way through that part of training. How many days are spent in the swimming process? what kind of swimming tests are required just to p? does any of it depend on your marine vocation? does something like military police or security force pardon you from certain swimming requirements that infantry must have? I have wanted most Navy seals but that clearly means the ocean its self and certainly means timed long distance swims. though how does USMC minimum requirements compare in the military today? Thank you very much. Please report feed back if you can help me better understand this situation. Peace, God bless america,and everyone serving it!