Help me please

My daughter is 6 months old and she keeps screaming when we put her in her cot at night time, even though she's already fast asleep. I'm guilty of putting her in with us just to get some sleep but I don't know what to do. My mum had me and my sister in her bed until we was past a year old so she thinks I should just let her but I'm really focused on getting her to sleep in her own room again. She's been in her room since 4 and a half months. She's always fed, winded and changed before she's asleep. X