A couple of positive things:
-Your kids will be 10 yrs old when you guys are in your early 30s.
-You guys have the energy to keep up with the new born schedule. (I am 34 with 1.5 yr old and a one month old baby...at this point, coffee or energy drinks doesn't work for me anymore). But things will get better, you probably know this already.
-at age 21, i had the an used Supra turbo MkIII. BMW was a dream to me. You have a steady job, a family and a BMW. (don't regret any of it, enjoy it)
-As far as school and being successful. It seems like you are on the right track. So do what you have to do and get thru it. Jump to another job or climb up from your current position with your degree and see where it takes you.