Trying to break

How do I break my 20month old daughter from having to be cuddled to fall asleep, she sleeps by herself but still needs to be help to sleep. I know it needs to be done soon as her baby brother will be here soon. I always feel bad for thinking about breaking her. I think it’s because when she was born, she was taken to another hospital with a nicu because she was early and couldn’t breathe on her own. I basically have hard time letting her go, I literally just let her be watched for the first time ever by a family member. This baby is extremely likely be born before 32weeks and I’m going back to when she was born so it’s making it hard to let her be a big girl and sleep on her own. I don’t like the crying out method either. Idk what to do 🤦🏻‍♀️. Any help