Every service requires a degree for commissioning. If you want to go shooting that's one thing and shooting in the USMC is another. The Marines have always taught their people how to shoot a rifle. I wouldn't worry about that as they have taken millions of people who never touched a firearm qualify expert. You are better off exerting your energy in PT, running, pull ups, situps, and push ups. Those are the things that will kill you if you aren't prepared. I was an Army guy with over 40 years AD, Guard, and Reserve.
A friend of mine's son became a SEAL. After he was accepted for training (that includes the 5 mile ocean swim and 10 mile run). He wanted me to teach him to shoot (I've been a police firearms instructor for over 40 years and taught people everything from a 22 to an 8 inch howitzer). I told him I would give him a taste but he was better off waiting for the Navy to teach him. That's what we did and he's been on a team for about a year. In another year, he'll be teaching me stuff I don't know.
A friend of mine's son became a SEAL. After he was accepted for training (that includes the 5 mile ocean swim and 10 mile run). He wanted me to teach him to shoot (I've been a police firearms instructor for over 40 years and taught people everything from a 22 to an 8 inch howitzer). I told him I would give him a taste but he was better off waiting for the Navy to teach him. That's what we did and he's been on a team for about a year. In another year, he'll be teaching me stuff I don't know.