Should I get Married?

I am 22 yrs old, in the military and going to college, the girl im getting married to i know since high school, lives in another state and has an adorable baby girl (not mines). I love them both so much but part of me does'nt feel to confident. She is a bit younger than me, not going to college.. in fact she never finished high school, she admitted to getting rides from other guys?? yea i know right.. Also she is a very sexual individual... so it bothers me because how is she really going to act when i leave for a deployment? Is she really gonna go to college like she said she is? Is she going to get a job? and the guys she tends to date are like thugs and dope dealers... is that a bad sign? what is everybodys opinions? my family supports me but only because they love me... deep down my grandma says im too young... AAAHHH what do i do? Could this spell "Future Divorce"?