Baby won’t sleep?!

So when my daughter was born up until about 10 months old she would sleep 12 hours a night and would not wake up at all through the night She just turned 11 months old today and for a few weeks now she hasn’t been falling asleep until 11 pm or midnight. We thought it was because she had a cold but now she isn’t sick and it’s still happening. I don’t know what to do... I am a first time and a teen mom so I have school in the mornings...anyone have tips...

Also I know being a teen mom is criticized and I made the choice and I know it’s tough and I need to deal with it being in school and such so please no hate I just need advice I have no family to talk to...