Instead of looking for people to "blame" about whether its her fault of your fault, think of it this way instead:

Maybe shes' a lesbian
Maybe she prefers fat men
Maybe she doesn't like fat men
Maybe she prefers tall men
Maybe she prefers short men
Maybe she's married
Maybe she has a boyfriend
Maybe she just had a break up and is happy being single
Maybe she just isn't looking right now
Maybe she had a fall out with a friend
Maybe she just wants to have a good time with her friends & not be pestered by giys

There are a very large amountof factors as to why she isn't interested, some of them are related to you but many of them may not be. As i said in the above post, why not just accept that this is life, smile and move on? Let it go.