long distance relationship Scorpio&Gemini-Cancer?

I'm a gemini-cancer, not in early 20s like your gemini-cancer guy though, I guess I still can give my two cents?
When I was 20... well, never really took myself seriously nor any relationships... it was all about fun, fun, fun - having more fun. I had some great romances which led to long distance, but never expected them to last nor planned to pursue them, because:

1) with most guys whom I had long distance relationships with, I had spent rather short time together with them, like, from one month to a half year to max 2) I was too young - back then, romance comes and goes quickly and quite easily - so many things can happen in a very short period of time 3) being young again, meant that I had lots of other things going on - school, future plans, friends, self searching, etc. Romance was just a part of those many things I went through & experienced, not my top priority back then.
Personally, I wouldn't invest too much in someone who I only spent five days, especially when myself being 20-year-old... but like I wrote right up there, 'personally'... it could be a different story with you and your guy.
Just my two cents. Hope you find this helpful!