If you start dry hopping too early you'll probably blow out most of the hop essence/flavor/aroma during the most vigorous stages of fermentation, especially with what is probably a rather high OG. After that, assuming you're fermenting in primary for the standard 2-ish weeks, you might get some grassy flavors in the final brew as a result of leaving those hops in there too long. Conventional wisdom states that you should leave your dry hops in the fermenter no longer than a week, and only during the final week.
Fear not, it's not ruined yet. You have a couple of options. If you're fermenting in a bucket, all you need to do is fish those hops out of there if you're worried about it. If it's in a carboy, what you might be able to do is rack into a secondary after the most active stage is complete (inside a week, usually) and go from there. After that, you can add more hops for dry hopping. Your fermentation schedule will decide when you add more hops for that purpose.
As far as using your own hops goes, it should be fine assuming you've prepared them properly. Wash, dry, refrigerate, etc. You can use them fresh but I think most people dry them first. I'm not completely sure of the specifics as I've never grown my own hops, but I do know that hops have natural preservative qualities. This is why people generally have no trouble with infection due to dry hopping and whatnot.
Edit: So yeah, don't worry too much. Like you said, it'll still be beer even if you don't do anything else to it. RDWHAHB.