What is your childcare situation going to be? That’s the most important factor.
As a mom with a baby and a toddler, I went back to (the equivalent of online) college for a masters degree. I took two courses, both requiring a lot of reading and writing. I’m sorry to say it didn’t go well. I had a paid nanny and I simply couldn’t manage the work. The needs of the children sucked all my time, even with paid help. I had to drop the courses.
It may not be the same for you. But I would start with only one class and see how you manage the time.
If you aren’t expecting again, and you’re determined to get a degree, perhaps hold off having more kids until your current baby is older and a little more self sufficient. I think in my case, it was the baby that made the situation unworkable. It would have been difficult enough with just one child.