Kids want their own phones, am I crazy for saying no?

My 10 and 12 year old are begging for phones like every other kid in their class apparently has. I feel like I'm the bad guy but something about it just feels wrong. They can use tablets for homework and stuff but owning their own phone feels like a different thing. Anyone else holding the line on this or am I being unrealistic? What's the actual age you guys went with?