Besides the points about not sharing products I haven't bought/tested/tried/etc., your page is not visually appealing. It's hard to take anyone claiming to 'design' shirts seriously when their launch page is poorly designed.
Things you could improve:
* Use a nicer font.
* Use horizontal space more effectively.
* Even if the shirts were great, tweeting about 'HappyNerdShirts' is just asking my friends to flame me.