The site
http://littlepleasures.org doesn't have an age verification thingy. It just assumes that you are at least of age if you buy. Also, when I have bought stuff, it shows up as LPGifts in your charge statement, so nothing suspicious at all. They also don't have a mailing list, just email, but you can opt out of that. They only email once every couple months, anyway.
For a first time vibe, I would personally recommend something with a soft body that has some give in it, if you are looking for something to insert. Something like this:
http://littlepleasures.org/my-secret-vibe.htm
If you just want something for clitoral stimulation, I would go with a pocket rocket:
http://littlepleasures.org/pocketrockets.htm
If you want something very discreet, I think the duckies are just adorable:
http://littlepleasures.org/i-rub-my-duckie-paris.htm
On a side note, I would have loved to have been able to own a vibrator at 16. I started masturbating at a very young age, so I, like you, already knew how my body responded to stimulus by 16 and just wanted to try something different. Good for you for embracing your sexuality!