I've been through this twice now and the thing that kept catching me off guard was the math on timing.
most companies have two promo cycles a year, maybe one. if you miss the nomination cutoff you're waiting another 6 months minimum. so "you're on track" from your manager in April might mean "earliest possible outcome is November." and if calibration in November goes poorly for any reason, you're now looking at the following spring.
you can do everything right and the answer can still be "18 months from now" just because of where you started in the cycle. I'm not saying this to be bleak. I'm saying: build the timeline backward from the cutoff dates, not forward from your last performance review. ask HR what the nomination window is. it's not secret information. most people just don't ask.