Well, you could read up online about face shapes and hairstyles to maybe get a bit of an idea. I know there are plenty resources for women, I hope men aren’t left out.
But honestly, from what I saw, long hair rarely looks bad. And even if it doesn’t completely suit the face, lets be serious here, the hair itself is magnificent enough to compensate for everything else.
I say go for it if you want to grow out your hair. If you will be comfortable and happy with it, then that is all that matters.
You definitely got our support! When it comes to long hair I think it is very hard NOT to look good with it :)
Much luck on your journey and don’t give up during that awkward-hair-length period. I have seen too many brethren stray away from the path of long locks because of it. Be not dismayed!