Yeah to my understanding Ralph's is pretty strict about all their events being 21+, they have that on their FB page and all the fliers I see will say 21+ on them. But, you could try I guess - worst that happens is you get turned away.

For house shows and stuff I think if you are able to find some bands through social media you can at least get info that way, so you might have to dedicate some time to social media stalking local bands lol.