Dilated!

Hello ladies

I had an appointment today and have been feeling aching in my lower back and cramping. This is my first pregnancy so was thinking I might be crazy and overthinking it all...but doctor said I am 1 cm dilated! I read that it could take 2-3 weeks or 2 days (no real science) to actually give birth but wondered your experience with the production of labor on your first time babies.... once you found out you were 1 cm...

Thank you!