AITA for not wanting a second dog?

I (32 F) and my fiance (32m) have a wedding date set for 3 months away. We are wedding planning, completing house renovations, and my fiance is contemplating a career change, which would require him to go to college. My fiance has requested that I take care of the house while he works night shift and goes to classes during the day, which I've agreed to. He would take an accelerated program for seven months, then finish classes at a community college for 2 years. Currently, we have one dog, and both work full-time. He has asked for a second dog before, and I've declined until after our wedding. This was before his decision to attempt a career change, the career change has only been over the last several months. The other night, he brought up getting another dog the month before our wedding. I said no due to our current stressful and unpredictable schedules now, and I informed him I'd be very overwhelmed with a puppy if he was away at school and work most of the time. He told me it was no more effort than putting another collar on a dog and letting the older dog train the puppy. I disagree with that statement; puppies take training, socializing, and a lot of time for their care. We also want to have a child the year after our wedding. I cannot imagine myself pregnant, home alone, cooking/cleaning, working full-time, and providing care for 2 dogs, while he's away from the house for 16 hrs a day. He called me selfish to saying no to a second dog. AITA for wanting to wait to get a second dog after he finishes school and complete his career change?