Does 18 really mean adult?

I jut want some feed back on what I have ben wondering. My daughter will be 18 in July. I personaly dont get it. I feel that 18 is just another number, big deal so now she can vote, be held responsable for her own actions. Why is it not my responsability anymore, just because she is 18. I feel very strongly that if she is still at home that I should still have say so on curfew , parties, boys, ect. I honestly do not feel that I am being controling. She lives at home, we are paying her way. If the law thinks an 18 year old is an adult, why is the drinking age still 21. I feel that 18 is still not a age where they are mature enough to make adult decisions....They still need guidance in my eyes. Do you think I amright or do you think I just don't want to let go?