27 joining the military?? (Context needed)

So I turn 27 this Sunday, and am thinking about joining the U.S. military. And would like to get some thoughts concerning pros and cons. (Quick and dirty background info): I'm a W 27 M, 6' 0, ~170lbs, lived in Alabama my whole life, decently athletic especially if training, sort of a bad knee but not too bad, got an associates degree in metal working/ fabrication/ machining, few years of experience, sort of had a bad run the last few years, lost my gf, my dad past away, lost my house, moved back into my moms, so you can imagine why I might be wanting a signif. change.. I want to see the world, face new challenges, have new experiences, learn new things. I've always had a calling to the military just about all men in my family have served in just about every different branch. I'm heavily attracted to the seals but honestly don't think I could cut the cheese... maybe army, but I would potentially like to get to use my head more, so maybe Air Force.. also the thought of being on a ship (navy) sounds kinda cool to me as well, at least for the time being lol. Marines, seem too serious and hard Ass idk, also not sure if that's the best fit. Thoughts?