Will i be charged for internet usage?

My dad has an iphone and before he got it my internet and picture msging was blocked on my phone so i wouldn't Rack up the bill. Now that he has an iphone you NEED the internet for it to work. Last night i used the internet on my phone will i be charged? im pretty sure we have the same data plan cause my mom, dad , have unlimited texting. We get our bill online so ya