Welcome mchawking!
Was good speaking to you on the chatroom the other day.
It was Muhammad's marriage to Ayesha which started the landslide of doubt for me also, and I too was very wary of "anti-Islam (i.e. any website criticising Islam)" websites.
That's interesting how your dad is dealing with this right now, sounds a lot like mine. A kind of agreement to disagree. I think that's the most we can ask from Muslim parents. Did he put any T & C's on it, such as visiting sheikhs, etc?
I think what car313 is saying is that people here don't mince words on Islam, we call a spade a spade. Also, don't worry that you haven't studied religious philosophy or whatever. You are young, you have time. I myself an agnostic, though I know I will never return to Islam. There are many types of atheists too.
Enjoy your stay!