Baby 4 month old

Hello mummies, just wanna ask .. my baby dah masuk 4 month.. berat 7kg.. Time mlm, kadang2 he sleep jam 9pm bangun jam 6am.. and kadang 8.30am till 5 am? Okay ka tu? In between time jam 10.30pm I will wake him up, untuk feeding.. lepas burp dia tidur balik.. kadang2 risau dia tidur lama..