Pro tip: if you're new somewhere, don't ask "can I become an admin". It only decreases your chances of ever becoming an admin.
Admins are selected from the ranks, rarely if ever by self-nomination. The choice is based on quality edits, knowledge, community involvement, and the choice is then presented to the users, who can vote on yes or no.
Seeing as, apart from Young Justice: Legacy, YJ is pretty much dead, and the vast majority of content has already been written, I wouldn't get your hopes up of becoming one of the highest quality editors - you'd need to catch up a lot. And people are promoted to admin status if there's a need for additional admins, and at the moment, we can manage.
Just to elaborate on a thing I only mentioned in passing above: We've had an image of Bart as KF. Even that image you added, though that had a better ratio (we prefer 4:3). That, and several others, was discussed. At length. But ultimately, it was decided, by the community, that the current image should remain Impulse, and a Kid Flash image should be in the relevant section of his history. And we decided not to move the page.
Because we like to keep a permanent record of stuff. If you're not comfortable with everything you do having a permanent record, you should reconsider contributing to wikis (and posting on Facebook, for that matter!).