I am a 30 summoner as of today and want to vote in the tribunal. It tells me I am not 30, do I have to wait for a day or somethings for it to know im 30?

Your forum tag still says member. It may not have updated yet.

I'm pretty sure the forum tags are just based on the number of posts a user has made.

You might have to wait for a daily rollover. In a less ideal scenario, it'll only update during the weekly downtime. In the uber worst scenario, its bugged and not letting people in who turned 30 after the initial test launch.

I hit 30 4 days ago and it was still saying I wasn't 30 yet this morning.

Then I logged out of the site, and logged back in. That fixed it for me. They must store your summoner level in the web cookie. Kinda dumb, but whatever. I feel like an idiot that it took me 4 days to try that.

logged out and logged back into the website and it fixed it for me as well

Well, hopefully your 4 day delay caused you to post about it on the forums, and now other people can benefit from your experience. So, it wasn't all bad!