I had children young. I was a little younger than you when I had my first. I didn't finish college the first time around. I had to work at low-paying jobs. It wasn't cost-effective for us to have me return to work once we had the baby - child care is very costly. So I stayed home, and put my "career" on hold. Made a couple of more babies in the meantime.
After the third, I realized that if anything ever happened to their father or if I ended up having to raise them alone, I would not have the skills or the income to give them a decent life. I went back to school full time for three years, with student loans and bursaries (kind of like scholarships) to make things easier. It was hard, HARD, HARD work. Even if my husband had been completely supportive of this venture (which he was not) it still would have been HARD WORK. But I'm a stubborn old bird and once I've made my mind up to get something done, I have to see it through to completion. And none of this half-assed stuff with Cs and Ds and barely passing by the skin of my teeth.... NO WAY! it was 4.0 GPA and nothing less for me. When my husband would complain about my studying, I'd ask him "When you go to the hospital next time and you need a shot of pain killers in your ass, do you want the nurse who barely passed? or the nurse who was at the top of her class?" (No I did not have a minor in poetry ) Would I do it again? It was really worth it, to me, so yes, I would. Could I do it again? I don't know about that....
I can understand the callings of your biological gong, but it will be easier, both for you and your family (whatever size it may be) if you finish your schooling - get your Bachelor's degree at least first. Take a year off from studying, save up some money, and then revisit the issue of having children. If your husband isn't ready right now, and you have children without his complete support, he'll be resentful and that's not a great start to family life. You are still very early in your fertile years - in my practice, I see women in their late 30s and early 40s having their first babies - and they are ready to take a sabbatical from their careers and be completely devoted to their babies. Many of them also have the life skills to have a career from home if they so desire.
I can tell you from personal experience that the ticking of your biological clock will quiet itself. It tends to go in cycles. When both you and your husband are ready to embark on this adventure together, you'll make great parents.
Love, Scully