Happy birthday!
Yeah, not much changes, really, at least not immediately. I'm still not sure I would say a lot has for me, and it's been two years. I feel a lot weirder about my age having acquired a new digit in the tens place on Monday than I did when I turned eighteen.
In my case, the biggest deal in turning 18 was obviously the right to vote. I had been looking forward to it for the past 5 years at least, and voting for the first couple times was one of my most exciting moments (further reinforced by the fact that my first vote was part of a historic and largely unexpected victory).
That was the case for me, too, but I didn't actually have an election to vote in for nearly a year after my eighteenth birthday. Having those referendums as your first vote is also a lot more interesting than the Democratic primaries for (if I remember correctly) various municipal offices and Massachusetts Northwest District Attorney.
My first vote is likely to be for Terry McAuliffe, unless the Green Part of Virginia gets it's sh*t together and runs a candidate or some independent runs. Ugh. Not very excited about that.
legally have consensual sex
Depends of the state (might be 16, 17 or 18). In this case, it's 18 in Virginia (which is ridiculous), but 16 in your home Oklahoma.
It is kinda ridiculous that if I go 5 miles over the Potomac it was legal for me to have sex but here in Virginia it wasn't. More proof that VA is a terrible state. Thankfully I'm getting the fyck out of here this fall.
Regardless, it's now legal for me to take/send/post nude pics of myself everywhere (another weird inconsistency, that it was legal to have sex but not to take pictures of it in many places), which I may take advantage of soon ;p.