It's probably not too late but you'll need to do it slowly and with lots of love.

Maybe start by making the cot a fun place, play games through the bars, blow kisses read stories, don't even start making it about sleep.

Once she sees it as a comfortable place with lots of fun, start putting her down for a nap. I think, if you can handle it, you need to stick with your decision. If you change location in the middle you're just confusing the issue.

If she won't go down, just get her up. Start with the nap you can most afford to lose, maybe the morning one and then she will wipe out when you go down with her later.

Personally I have never coslept with my son, far too paranoid as I have sleep apnoea, am oveweight and my husband has MS and sleep walks, waves his arms around etc. But I use to cuddle DS in my arms for his naps and went through a similar thing at about 12 months where he just wasn't getting the rest he needs in my arms.

good luck hon, worse case scenario you're together in bed for a lot longer and that is quite lovely too!