Avocados are tropical and will not take frost. You will have to grow it in a pot. They are trees and grow large. Whether you can get it to fruit in a pot, I don't know but it will take a while. Somewhere I seem to remember something about some varieties needing another tree for pollination.

Yo!

Avocados huh? from seedling too!?
hmmmm..... do yourself and your girl a favor and get a GRAFTED plant, which will fruit in about 1or2 years, while from seedling will take from 8-20years for fruiting, and you can't tell if the seed will produce a good tasting avocados until fruiting. But GRAFTED plant is from the best tasting and fruiting mature tree's DNA, (clone) Which a plant is only 1or2 years old and think as of itself a 30years old tree and will fruit. All my fruiting trees are GRAFTED.
Go to Tropical forum, u'll see alot of post about avocados.

Good Luck!

Tin