Learning how to play gypsy jazz was something that was beyond me for a long time. Jazz chords and scales were alien to me. I come from a typical pop/rock background. If you asked me to improvise on a 12 Bar Blues, I can probably do a decent job, since the I, IV V chord progression and years of butchering Clapton and Stevie Ray licks has created some sort of muscle memory there.
Gypsy Jazz on the other hand requires a different vocabulary altogether. It is more akin to trying to speak a different language. Even the techniques involved are vastly different. However, if you're a decent guitar player and you're willing to put in the work, you might be able to pull off some of it. In the last year or so have been putting in some time trying to learn it, on and off.
It has been a massive learning curve for me because I am not a technical guitar player and gypsy jazz requires a lot of technical ability in order to be played properly. Once you get into it however, it can get addictive. You have to enjoy practicing. Once you enjoy practicing, it will come to you slowly, just like with anything. The whole down-strokes only when changing strings is particularly hard to get used to. I usually use economy picking.
I don't see myself putting out any Gypsy Jazz music in the near future. It is purely for personal enjoyment. Might take lifetime for me to get it to sound decent, anyway. In the meantime, I am enjoying expanding my repertoire and improving the way I play. The journey should be as enjoyable as the destination.