At about 20 months we took the sides off DD's cot and she absolutely freaked out! Would not settle at all. So we put them back on and left it at that. For her second birthday we bought her a low toddler bed and put it in her room. I was dreading her reaction but she just hopped in it and had no problems from day dot! She is such a creature of habit I don't think a modification was her thing, she needed a complete new concept lol

We used sleeping bags in the cot but if I didn't she would try to climb out so I couldn't wean her off them before moving to the bed in fear she might fall out/over.

Went straight to sheets in the bed and she was fine, just tucked her in quit snuggly. She still insists on a good tuck in now and that's generally the only time she wakes now is to ask us to tuck her back in.

Good luck - you can only try and see how it goes!