It really depends on your circumstances. I've just finished 1 year full time study with a toddler and getting preg half way through... It was really hard for a few months when I had shocking morning sickness and hardly made it to any classes - I got lots of extensions! I also have a very supportive dh who works 4 days on 4 days off so he was around lots to look after ds.

If you have difficult pregs followed by bubs reluctant to sleep it will be very hard, but you could breeze through pregs and get a good sleeper, so you won't really know till you try. I say go for it, and know you can always defer if you need to. Good luck!