Second baby - crib transition?

Hi all! My son will be 16/17 mo when my next baby is born. I plan on keeping that baby in our bedroom for about 3-4 months and then transition him to his own room and crib. My older son will be around 19/20 mo then. Is that a good age for a toddler bed? I’m trying to time it right but I don’t want to be too disruptive to his sleep cycle. I also want to avoid buying another crib if I don’t have to. Anyone who has been in the same boat I would love some advice! TIA!