You're looking for tunnels, otherwise known as eyelets.
While your ears are healing between stretching, you'll want stainless steel or sterling silver tunnels. I HIGHLY recommend getting single flare plugs, not double flare - double flares are much harder to get in, while single flares you can insert with a ring around the back to keep it in.
It's important to note that at smaller sizes, you won't be able to wear tunnels - they aren't made small enough. Until then, just use circular barbells or pinchers.
^double flare tunnels (don't get this kind!)
^single flare tunnels (get this kind!)
^Circular barbells... Often the cheapest jewelry.
^Pinchers can do the job of plugs and tapers at the same time.
When you finally get up to the size you want and your ears have fully healed (I'd give it about 3 months just in case), I know you'll love a type of tunnels called earskins. They're made of silicone, so they're squishy and comfortable, and they make your ears look bigger!
^Earskins. They feel like thick and strong rubber bands.
You can use ebay (the cheapest method) to find exactly the plugs you want, or you can go to the following website, bodyartforms, for trustworthy and high quality tunnels.
^single flare tunnels
^Or maybe you like gold? (a little cheaper)
^The earskins I have... They're wonderful!
As for the issue of parental consent, anyone can buy plugs and tapers and stretch their ears themselves at any age. Some people prefer to go to a tattoo/piercing shop and have the piercers stretch their ears for them... I don't recommend this, because YOU know your pain threshold and when you would want them to stop stretching, but THEY don't. The "well, I'm here, so I might as well tough through it and let them finish" attitude has resulted in a few unattractive ear lobes (and a lot of unnecessary pain!) in my friends...
Getting your ears stretched for you by a piercer is the only case where I'd imagine your age should be an issue, besides ebay and its age limits on holding an account.
Have fun and stretch away!