If I'm over 21 but still using my I'D that hasn't expired yet, can I use it to gain entry and make purchase?

Yes.

If it is still valid...

Yes. If you have a valid Identification Card from any state and you are over 21 and your ID card shows your atleast 21, you may gain entry and make a purchase. Valid U.S passports work as well. You can even use a valid temporary ID card issued by Washington state with sn expired ID(for the picture) and not a temporary from a different state, then you may gain entry and make a purchase. Uncle ikes is a great choice of dispensary! Much love! ❤

The new law is: your ID must say you're 21 or over and it has to be horizontal. If you still have a vertical ID, you'll have to use your passport.

As long as it says you're 21 yes