Stay out of the Marines... they do no treat women well generally speaking. What do you want to do? What you want to do has a lot to do with which branch you go into. If you are interrested in the medical field, the Navy or Airforce are both good, down side to Navy is, they could put you green side and station you on a Marine base... I have been married to a Marine, and live in a Marine town... My husband is ex-Navy... big differences in their behaviors toward women.
Next major bit of advice, your recruiter WILL lie. NO exceptions. Even if you get it in writing, there is a little clause in the papers you sign stating nothing the recruiter told you does not matter unless it is a specific contract. Otherwise, it does not exist.
A recruiter for enlisted is not the same as a recruiter for officers... Always better to start at the bottom of the top pile so to speak...
Probably the best possible scenario would be to look into branches that will allow you to go to college (not necessarily their academy) and then allow you to enter into the service after you are done with college... many branches will pay for you schooling if you promise to do 6-8 years in their branch.
There are also CIA type jobs, Coast Guard, etc. I like the Coast Guard personally, but I recently looked at CIA type jobs and they had some very interresting programs to offer that included education...
You can go into a technical field. Concentrate on what you can take to the civilian world with you... don't be a secretary. Get good job skills for when you get out of the miliatry. Always think about what you want to do when you are no longer in the military. Even if you love it and stay in for 20 years, you will only be 38 and you will want another career or to take that career into the civilian sector.
US Coast Guard is actually one of the best branches if you want to travel, not the Navy believe it or not. They also have good helicoptor training. Army offers good Vet and Engineering types of things, and Biological, Nuclear... Navy offers the better Medical fields, technical fields (electricians, computers). The Airforce is the Corporate types of all the branches... they run things, good flight training, and frankly, nice. They are the businessy end of the military.
You can go to each branches web sight and see what careers they offer. But like I said before, always look for what you can take with you into the civilian sector and make money... the military is not for everyone, it is tough and physical, and most of us can only stomach 4-8 years before getting sick of people telling us what to do... especially those of us who are smart and think for ourselves.