Search Results: she is blowing me off

I was discussing my dating life with my older cousin again... And I told him recently I had added this guy on Facebook and asked him out myself. We had matched on tinder and talked a little, but then he disappeared and it was bizarre since he was just stating he'd like to talk somewhere else. I'm confident in my looks and in my inner self, I believe I am a good catch, and I thought why not give it a shot, otherwise we'd most likely never talk again, especially since I deleted tinder afterwards. I added the dude and he accepted, I asked him out and he replied he definitely would like to! When I had told my cousin this he really ripped me apart, saying I was so desperate, that the guy thinks "oh shit now this girl is so into me" and he is NOT thinking "oh cool this super pretty nice girl likes me, and she asked me out awesome" or whatever, my cousin's words. He said I will not be successful in dating EVER if I continue to "pursue" the man and take initiative. I rarely ever do but I told him this situation was different. The guy I'm after really has NO girl action on his fb, he is a super quite kinda nerdy dude... I honestly just wanted to get things moving and show interest... But apparently showing interest is a "no-no"? Why is it bad for a girl to show interest in a guy if she is interested? How is that coming off desperate or needy? It's not as if I am blowing him up, texting him 24:7, or messaging him needy messages. I'm honestly just wanting and trying to meet the guy.