Sez, I have been studying early childhood teaching via correspondence. I am in my final few weeks now thank goodness! I deferred for a year while I was pg due to the stress I was under at the time, so that meant that I began my course again in July last yr and will finish as soon as I do my final assignment. It has been pretty hard to get up the motivation since I don't have to go to classes. I have to make my own time table which is easier since I can do it when it suits me, but it's also harder because I have to make sure I take the time to study and not clean up or do something else. It has been easier these past few months that Lil has been bigger and sleeping longer stretches at a time. I have had mum look after her a couple of times so I could catch up when I felt swamped, the house work often suffered for it and DH had to help alot more too, but that was all good. I got things domne when I could and had to prioritise.
I would say that if you can do any of your course via correspondance, then that could be an option for you to start earlier. Maybe just do one module at a time. But if you want to actually attend uni, then I would say that after about 3yrs would be a good age to study. Then the children can entertain themselves to some extent, they have some understanding of you 'needing' to do things without them and not have you as their centre of attention.
Crazily enough as hard as things have been for a while, I am not deterred from studying at all and may very well do some more next yr, so if that says anything, it would be that it is doable!! And the sense of pride you feel for having done it on your own is great!!!
Good luck, I'm sure you'll do really well. You think it is impossible at the time, but when you get it done, it feels so good