I say go for it. Although my kids are a little older than yours, I was able to make it through. have a great support system is critical to your success. without my family I wouldn't have been able to do it.
since you have a little while before you start, you might want to work with your family on getting your 1yr old used to you being away. have someone she is comfortable with stay with her while you leave for a little while (to the grocery store or what ever) a couple days a week.