Will it hurt to put a 18 gauge in a standard ear piercing hole?

Kso, Im thinking of stretching my ears but not to huge like to a 10 or 8. I was thinking of maybe 18 .. will it hurt to put an 18 gauge tapers in your standard ear piercings? I got my ears pierced when I was just 3 months. Or can you find 20 gauge tapers?