I have a theory that they are making a live action movie of Young Justice because miss.m was in supergirl, ideas in the flash and Artemis was in arrow. Do te think that my theory is true?

Could be laying the groundwork, DC does include easter eggs about upcoming projects, (well, in the Arkham Games). But, that doesn't mean that Young Justice will get a live action. Be mindful that it's a possibility, but don't get your hopes up. I'll believe it when I see it.