I'm with Groink here.
If you're a mature male, what could you possibly have in common with an 18 year old woman? She's never worked a day in her life at a real job. She's never known a drink. She hasn't voted. Her world ends where her facebook ends. She's never lived, basically, outside the confines of what her parents have given her, if she had anywhere near decent parents. She's still a child. She just got out of high school for christ's sake.
At each phase in a man's life, there are women in that same phase who can understand the man, talk with the man, and emotionally and spiritually connect with the man. It's why people get married...they grow old and grow through life together, at the same emotional plane. When you choose someone outside your emotional level of development, you're bound to be unsatsified. Unless you find yourself, in your 30's and 40's, having a lot in common with teenagers. Which is strange.
The only reason old guys married young girls so many years ago, as the norm, was because it used to take men a long time to accumulate wealth to support a family, and by then, women their age couldn't birth children without health risk (tons of women died during childbirth). Don't try to convince me it's a "genetic" thing. It never was. It was always a socioeconomic thing. That doesn't exist today. Women don't die during birthing nearly as often. Women can birth children later in life than ever. Men don't need to be the breadwinners, as women do a fair job today pulling down money if they're mature and motivated. So if it's not socioeconomic, and it's not genetic, then what it is it that attracts old men to young girls?
I contend if you're in your 30s, and chasing high school tail, then own your shit. Admit you're into them for physical reasons (which makes you pretty creepy, but not "legally" creepy). But don't try and convince me that you can be both mature and intelligent, and also interested in the maturity and intelligence of an 18 year old girl. I'm sure there are a few of them out there, but obviously, that's not the norm when you're 18.
You're being immature (you're seducing a young girl who doesn't know enough about her own self to know better, and you're using your age as a quasi-authority-figure power play to seduce her, which is wrong). You're being superficial, of course. And you're being selfish, by playing emotional games with a young girl.
If you're a grown man, you should know better. The fact that you know better, and choose to act it out anyways, doesn't wash with me. But then again, we don't have to hang out, so more power to you. The law says it's ok, so beyond my own personal bias, I guess you're free to do whatever you want. Don't expect waves of support beyond the basal male responses of "oh wow, 18 years old, so hot".
If I caught you with my 18 year old daughter, I'd be tempted to unload a shell of rock salt into you with the 12 gauge. Not very legal, but I'll own my shit too.

Only reason I wouldn't is because my daughter would be, technically, an adult, and I'd have to respect her decision. Wouldn't stop me in the least from painting the old guy as a super creep.