I stayed at home until my youngest was nearly four because my research and experience led me to believe that an engaged, mentally present, well educated parent who wants to be with their own children and thoughtfully plans their time together (by which I don't mean anything unrealistic, just going to some baby and toddler groups or spending time with friends with children/ from antenatal classes and their children for some socialisation, going out and about to learn very simply about the world, walks, lots of opportunities to play and climb etc. lots of talking to the baby and two way conversations with toddlers, a bit of baking or play dough or fonger painting from time to time, and not just ignoring the child and putting the TV on) is better than most group childcare for under 3s.
A good nursery is better than a parent who isn't engaged with the child or indeed a parent who feels unfulfilled or stressed or out of their depth or frustrated staying at home.
Even when I was a "stay at home" mother I did actually work two evenings once DH was home to take over - from when each baby was a few months old. I worked a short day as well as the evenings for a couple of years when I only had one toddler and one at preschool and my mother in law was well enough (and offered) to look after the toddler and do preschool pickup once per week. So I was "mostly" at home.
I will say my pension took a battering and I feel I'm massively playing catch up with that, and I ended up totally retraining to go back to full time work as I was too far put of the loop and couldn't go back to my previous career - the part time and evening work was interesting but not something I could do as a full time career.
Be careful because you can make yourself poor in your own right much longer term than just five years (especially if you go on to have a second child in three years and five years becomes eight...) because of missing out on advancement (you might have moved into management in five years if you go back in twelve months) and because of pension poverty. You can't know now whether you'll be comfortable relying on your partner to be comfortable financially/ to be able to spend money as you see fit on yourself and your adult children, in twenty five years time...