They should get much bigger before any separating or they could grow from the existing stem. There is no need to rush to separate - tiny plantlets have less chance of survival.

It looks like your stem is in sandy(?) soil mix...and potted too deep inside of container.

Thank you. Its a cacti soil mix and the stem was left in the original pot after i had taken the cutting and i added some extra soil to cover the roots that had continued to grow.