Is it normal for your mum to push you so much?

Okay, this could get long;
I've never had a relationship and I'm 21, I've been into guys but nothing has really come of it. My sister recently got a boyfriend and his brother is 29 and divorced, so my sister being the smart arse she is..... Set us up.. We all went to the cinema, and I knew then I wasn't attracted. My mum then started pushing as well as my sister to give him a chance and I felt I was doing wrong because I didn't like him that way? Anyway it settled down.
Recently my mum has started again, so I got us all together as mates and we went out again.. And I didn't feel anything at all, I let him know twice I just want friends but the next day he invited me round to his house for a pizza.. I didn't really want to go so I said no.
Apparently he's been back to my sister crying ? So I feel awful and my mum is still pushing for me to go with him saying you have to start somewhere and EVERYONE is friends until they are engaged, I've told her countless times I don't like him that way and if I did go round to his it's leading him on.
The thing is I'm desperate for mates and I think my mum thinks I won't find anyone so I feel like I'm letting everyone down because I barely go out and that all my choices are wrong and not natural :( it makes me sad.. But I am trying to find friends and I'd much rather find someone my own way who I'm attracted to.. I'm happy going to the gym, cinema, bowling, swimming and to the pub for meals.. Not all that drinking shit. But I should like it shouldn't I?