It's not really a problem where you are at, but it'll be somewhat of a problem if you manage to reach mid-high 4 digit, because the maps you can farm will dry up. That's a long way away though, you'll probably end up picking up DT and/or stream maps before then if you end up making it that far.
Learning DT will make farming a lot easier though because suddenly the amount of maps you can farm will quadruple. HR is less viable if you want to keep playing jump maps, it's more viable for stream maps, and not really worth focussing on if you just want to one-trick aim, until you want to learn 3 mod down the line. HD is completely optional, it won't really make a difference whether you can play it well or not.