is that a realistic goal

I think you could do that in a year assuming your hearing is pretty good (which you can test on the site here), you have the aptitude, and you are consistent. it's all about SPI and the higher you level up in the games, the more SPI you get when you level up each time again. It seems like getting from silver to gold was pretty fast once I set out to do it. You will probably be better at some games rather than others. If there are games that you dislike or don't think are important (i did not like the reverb game), you can turn them off so that they do not show up in your daily workout.

Hi! As I see in the posts and comments everyone's experience is different. IMHO Don't be harsh with yourself, progress in your own pace, be consistent.
This is how my journey looked like with nothing extra apart from the daily workout. From zero to diamond.
(I hope you like a good graph as an answer just as much as I do)
I began at the end of november. You can see that it took like 2 months for the first click to happen in my mind, then 2 month later a sort of plato and gradually picking up the pace since.

ahh i see its a sort of rich get richer system, i thought the people with diamond had to been using this website daily for years and years

Also, this number doesn't mean a thing... Just practice (and use SoundGym) and eventually you will get better.

PS: always compare your mixes to PRO ones