Wrong for14yr old to ride ninja bike?

[Charlotte]

My dad traded my kid dirt bike for a ninja bike and i called him stupid for him thinking i was going to ride the ninja bike. he said it was alright and i still find it wrong because first he didn't even buy me the proper helmet for my dirt bike(bought a bicycle helmet) he says it's the same thing and to lighten up i still say it's illegal and him coming up with the idea is stupid!

 

[Mark]

A 250 Ninja is the best beginner bike ever made(light agile and very forgiving). As far as the helmet, I only use mine to protect my eyes from watering and bugs. .