Well I know how you feel all to well. My husband and I have been married for 5 years now and we're FINALLY expexting our first baby in early March
I was only 19 when we were married and my husband only 21. The second we said "I do" both families thought we ought to be popping out kids just because we were married I guess. But we wanted time to ourselves first. Then by about the second year of marriage I started wanting a baby sooooo bad! But my husband still wasn't as ready as I was and he gave me all the reasons we should wait and they were all the same things your talking about. Better job, better this and better that. When we would tell people that, they would always tell us if we waited for that we would never have kids because it seems that the price to have children is always going up. We were always financially ok we just knew that having a child would put us on a budget and I was willing to do that so that we could start our family. I'm like you I wanted kids while I'm still young. I want to be able to run around in the yard with them and watch them grow up.
Well my husband finally suprised me back in June and told me he was ready to start our family, then only three weeks later I found out that I was 6 weeks pregnant. We were already several weeks pregnant when we started "planning" and I know that even if my husband hadn't announced he was ready he would have been just as happy. But I just think that since we tried to plan it out the best we could rather than jumping into as soon as we were married like everyone else thought we should, it happened when it was supposed to. We're in the process of buying our first house and should be moved in, in just a couple weeks and things couldn't be better with us. Yes financially things will be tighter than before but it'll be ok. We know we're finally ready for this.
I know your ready now but if your GF is still in college and on her way to having a great career then having a baby could slow that part of her life down. I mean it could mean time off from school depending on her pregnancy and that would take longer for her to finish her schooling and get her career started. And more time befor she can be making better money. Like I said before I defiantly know how you feel and I really hope things will work out for you in the end.