Transition to crib

Please help! I have co-slept with my baby since about 2 months old (8 months now) and I really am trying to get her to sleep in her crib. Today for her first nap, I laid her down, and she literally screamed until she couldn’t breathe and became hysterical. Any tips? I can’t stand to see my baby cry like that 😓😭 I want to make this an easy transition but is that even possible now? Have I waited too long?

I breastfeed. Which is why i started co-sleeping.