1. visa concern is a joke when you have a solid reasonable study plan.
I guess trying to get a master that can leverage your previous working experience (or your husband one) will be a better idea. (but it really depends on you, and your husbands background, both academic and working)
2. have baby later. timing issue.
biological, it is not a big problem for female before 35.
economically, it is not a big problem for the bread winner before early forties. (+20-25 years till university graduate = 65+, still at the edge of retirement)
visa-wise, >30 will start to have decreasing score, not to mention settling down with a baby is much more troublesome.