In some ways you probably are too young but I'd still say you could. What are the biggest concerns of your parents? If you're allowed to wear shirts that show your stomach anyway don't see why getting a black one and using it instead of the bikini would be an issue. Also, if they allow you to wear things that show some stomach you should be able to have the jacket somewhat more unzipped, at least some of the time. You could also lengthen the shorts some like what was mentioned.
Even if you do the full modification that's been shown I agree the jacket and hair are probably the biggest things that make her. And if you have one of her weapons that just makes it pop more.
I also agree of not making it 100% accurate right now and sneaking it past your parents. Because honestly if you're living under their roof and aren't supporting yourself they kinda have final say no matter what other people online/irl think.
Tentative Debuts for 2013
Kululu/Kururu gijinka (Sgt. Frog)[85%]
Male!Angel Anarchy Panty (Panty and Stocking with Garterbelt)
Laxus Dreyar (Fairy Tail)
Kagamine Len (Vocaloid - Ah! It's a Wonderful Cats Life)
Rarity (Original Design gijinka)
Kaoru Hitachiin (Halloween episode)
-Maybes depending on time/money/plans
Braeburn (Original Design gijinka)