Seedlings don't grow true to the parent they came from, they could be better but most likely they will not be as good of a cultivar as what you could buy at a nursery. Your seedling may or may not have good quality fruit when it matures.

Another factor is the roots. The seedling will have its own genetic rootstock instead of rootstock that has been bred to control tree size and promote fruit production. I have a Frost peach that I rooted from cuttings when I planted a Frost peach grafted on semidwarf rootstock. The self rooted tree is 10 - 11 feet tall, three years old, and has two peaches on it. The grafted Frost peach is 6 feet tall, four years old, and has had more than a dozen peaches on it each year since the year after I planted it.

One more consideration: in Vancouver BC, like in Western Washington, you probably will have peach leaf curl problems. There are a few selected cultivars that are resistant to curl. Frost, Q1-8, Avalon, Indian Summer, etc. Your seedling might die in only a couple years from leaf curl.