Changing from a cot to a bed?

[Tommoson]

Hi so DS is a bit older. He's 3 but co slept for a while. He's been staying in his cot the whole night for a good 3 or so months now? We're very proud He's doing fab

We still have the side up as we.wete going to use the cot for younger DS when they go to their room

But before he gets a single bed do we take his cot side off first? So it's not so new to him. He doesn't try and climb out or anything

Tips please

My kids went to their own beds at two. Or just under. The twin bed was against a wall and I remember with my son I had a rail in the open side initially. I don't recall doing this with my daughter though. My son moved as his sister was born needing the cot. No issues with either transition - both pleased as punch to be moving to a 'big bed'.