You need to really think hard and find the answer and have peace with it. If you go to school or get a full time job, will you regret not having another? Or if you have another, will you resent that you didn't go to school? Neither is a healthy attitude.
Could you start school now, til you get pregnant and maybe thru the pregnancy. Take a break when the baby comes and then do school part-time or online when baby is a little older? And finish up by the time baby is in pre-K or K?
I was 34 with a 10 year old and 7 year old when I got pregnant with my youngest. I was 35 by the time I delivered and it was no big deal. I worked full-time thru the whole pregnancy and after. I will say, it was a lot more tiring at 35 than it was the first time at 25 LOL. Both of my kids were a big help though, then and now - my kids are now 18, 15, 8.
Only you know the answer......good luck.