How can you tell when baby has dropped?

Keshella • ♉18♉ 👣Mommy to a baby boy born 09/25/16👣 💜Happyly taken💙🎓Graduate🎓 🐧First time mommy🐧
I was wondering how can you tell if your baby has finally dropped. I feel like my son has dropped but um a first time mom so Im not so sure.