Enlisting at 26 with bills that need to keep being paid?

Things are currently not going so great in my life, and as such I find myself thinking back on the one thing I always regretted not doing; Enlisting straight out of high school (debating between army or air force). I don't have any sort of career currently or even any plans for my life since I never even thought I'd make it to this age, which brings me to my first question.

1. I've always wanted to enlist as infantry. 11B. Would that be worth it and would I get anything out of that that I could apply to my future (outside of law enforcement), or should I go for something else?

2. I take medication for depression, will that be an issue at all?

3. I can do about 13 push-ups, 2 sit ups, and no pull-ups. Is that good enough to get in, or should I get to a certain point first?

4. My main question as of right now. I have certain bills that need to continue being paid, including pitching in for my parents rent. Is there any way that my base pay can be negotiated? I'd be looking for at least $3000 a month (in addition to any housing / food / whatever other pay).