WSM - i'm not the person you were asking, but thought I would give you my thoughts on the matter.
I started the Advanced Diploma in Midwifery when my ds was about 25 months. It is possible, but it is really hard work and you spend most of the time just wishing you could be 3 different people at once. As it happens I didn't finish the course - I had to leave near the end of Year 2 because of problems my ds was having (he has since been diagnosed Asperger and ADHD). It was hard - I felt like I wasn't giving my best to anyone - not to the college, not to the hospital and most importantly not to my ds. So I had to make a choice.
However, most people on the course had children, and most of them managed. It can be hard to arrange suitable childcare for really little ones, because in many Trusts you will be working ordinary hospital shifts, and it can work out quite costly from that point of view. Although if you have family who could help then that is ideal?
Really I think it depends how much you want it - if you are not really comminted to the idea then I would leave it (certainly until your youngest is older) because it is SUCH hard work. However, I found Midwifery one of the most rewarding things I have ever done in my life - I miss it passionately and am determined that I WILL get my chance again, although I am afraid I am expecting a baby myself now, and couldn't consider returning to midwifery until the child is nearly (or actually) school age. Although that is probably more a guilt reaction because of my son's problems than anything else.
So if you really want it it is do-able and worth all the work - but be sure it is something you really want first!