Different fruit trees, even of the same variety, will bloom and bear at different ages. They are not all the same. And just because they bloom doesn’t necessarily mean they will set fruit the first year they bloom. Another risk is that if they bloom and you get a freeze, the freeze can prevent fruit set. That happened to me this year with peaches and plums. But one good thing about apples is that the trees set blooms for an extended period of time. A late freeze is unlikely to totally prevent fruit set with apples because they keep blooming, though it does happen.
I’m not sure what growing zone you are in, but both Gala and Jonagold are good for a pretty cold area. I think you re fine with those varieties from that aspect. Many fruit trees need a certain number of chill hours to set fruit. I often get better production from apple trees after a really cold winter than after a fairly warm one. But if you are buying new trees it’s best to check your growing zone against the specific variety of apple.
While there are a few self-pollinating apple tree varieties, most require a different variety for pollination. Even the self-pollinating varieties normally produce better if they have a different variety as a pollinator. Some varieties are not good pollinators though. From what I read, Jonagold may be one of them. While it is best to have another pollinator within a couple of hundred feet, honeybees will travel up to a mile from the hive so they don’t absolutely have to be that close. Most of the pollinators I see buzzing around aren’t honeybees though, but smaller different insects, mostly bees of some type. If any of your neighbors have apple trees or even crabapples that bloom at the same time, you probably have pollination covered. Many commercial orchards use crabapples as pollinators because they bloom so well for so long.
Good luck on getting fruit this year. If you do, don’t expect to get a lot. At least that has been normal for me the first year. If you don’t get any, even though it bloomed, don’t be too disappointed. Next year should be better.