I honestly reccomend going to college first. That way, like you said, you have something to fall back on. Not only that but the more college credits, the higher the rank you'll get when you go in. I only have an associates degree in science but I went in as an E-3, which is great because I'll be an E-4 in September which is a petty officer third class in the navy. My friend joined right out of high school and it's been three years since then and she's BARELY making E-4. Plus if you decide to get your bachelors, you can go to officer candidate school instead of coming in as enlisted and then transitioning to officer. You could be a captain or commander within ten years of being in. (I'm using the Navy's ranks of course since that's what I'm in. I don't know the other ranks haha.)