Well, my grandpa quit going to school when he was 12.... By the time he was 45, he was able to buy his own land and build his own house. Now, I figure that if he could do it, then so can I.
Which type of faulty logic do these lines contain?
ad hominem
The faulty logic in these lines is called "hasty generalization."
http://writingcenter.unc.edu/handouts/fallacies/
Scroll down to read about the different fallacies.
This is probably Post Hoc or False Dichotomy, but you'll need to read through all of these to determine the answer for yourself.