Yes, start, but only take one class at a time while your kids are so young. There's no rush. Just get started. Take as much as you can online.
I have an educational doctorate and the money is good, enough to pay student loans. I started going to school at 25, divorced with young children, but I went back and forth from full time to part time as needed. I'm now in my 50s. I took a year off during my undergrad because of my kids. I also did everything online after the bachelor's.
Anything in the health field is going to be good, but a nurse practitioner will give you a lot of options for working part time or full time and which shifts you want. Administration would pay more after you get up there with experience, but it's probably going to demand longer hours with little or no flexibility.
Nursing is needed in so many areas, from visiting nurses in homes, to hospitals, clinics, doctor's offices, peds, sports medicine, therapy, to nursing homes. The pay would vary greatlly, but you have a lot of options to choose from that would work best for your family.
Just start and keep plugging away at it. You don't need to do it fast and burn yourself out and miss out on your kids and family life. 7 or 8 years will come anyway, so you might as well be working on a nursing degree or whatever you want to do.