Worried about disagreements on parenting

Hi all, my husband and I got in an argument last night and I need some advice. We've been together 7 years, married 1.5. I always wanted kids before I turned 30, and have a high chance of having difficulty TTC due to health issues, but he's consistently put it off (I'm 30 this month). Recently he mentioned that maybe he only wants 1 child (we'd previously agreed on 2-3) and last night we had an argument about flu vaccinations. Although partial to a natural lifestyle, I also believe strongly in vaccines and understanding science (I'm completing my Phd currently). I asked him whether he would want our children to be vaccinated against the flu, and he refused to answer, skirting around a response, saying instead that he believes in building up the immune system in other ways (I don't disagree with that as an addition to vaccinations). I'm concerned that he refuses to give me a direct answer, and on top of the delaying and changing mind, am starting to worry about our potential as parents. Does anyone have any thoughts/suggestions?