Well I was baptised catholic. I went to church when I was a little kid. I stopped going and never went back. I do not go to church now, we do not talk about religion in our house. I do not beleive in the whole thing.
Ah...this is what I thought. Not many people realise the over-reaching power the catholic church has.
You are indeed baptised catholic.
It is, however, not a genetic or hereditary trait. Now that you're an adult and profess to be not religious, you should no longer say you're catholic. And since Enmos asked, the question is not if baptism is irreversable...it's if the person baptised chooses to continue identifying themselves as the religion their parents had him/her baptised in.
You and many others however appear to accept the baptismal mark as irreversable even if you no longer hold the tenets of the religion to be believable. A baptism is wholly ceremonial, and completely irrelevant to your identity if you no longer subscribe to the originating theism.