I think if you want to get a degree then you should try to do that before you have children.
It's absolutely not impossible to do it after, some people do but you have to be realistic about when that would be.
If you have a baby at 19 and want to be a SAHM to care for that child then you will be doing that till they go to school at 5 (4 if they have a late summer birthday) so you'll be 24.
Except school is 9am-3pm, factor in drop off and pick up time and you will only be able to do a part time course unless you can afford and are willing to use after school club which adds anything from £200-400 a month to your budget.
If you wait till secondary school when your child would be able to get themselves home from school p, then you'll be starting that degree when you're 30, finishing at 33/34 and then embarking on your career.
And that timeline and budget assumes you only have 1 child.
If you chose to pursue a degree with an infant then you are looking at £45-70 per day for childcare before they are 3 years old with 15 hrs free childcare a week from the term after they turn 3.