Legality of 18 year old dating with a 16 year old over phone or just straight dating?

I live in Texas, We barely ever hang out since we dated so if her parents get mad they cant say i d her or anything, She has said to me that her parents are cool with it, but i have yet to talk to them about it. Is this illegal? and if i told the police she had told me I could date her does this help? jw..