I think it's funny how people talk about 50's top speeds- they're meant to be limited remember. As a 16 year old, technically if your machine is capable of more than 50km/h (on the flat I assume) then you're riding it illegally, your insurance is invalid and you give all young riders a bad name.
RS50s are a waste of time, especially restricted, legal, ones, although derestricted ones aren't much better- all noise, gearchanges and no go. Braaap, braaap, braaap, ooh 30mph, braaap, braap ooh a tad quicker. Don't believe all the claimed top speeds you see on the internet either. Just get a twist and go, quicker in the real world.