My friend owes me money, I don't know what to do about it?

My mum bought mine and my friend's ticket for Leeds festival this year, and she said her mum would be able to pay my mum back straight away, as in 2/3 weeks after buying them. It's May now, and she still hasn't paid anything. I feel so bad and pushy whenever I bring it up to her, I usually just ask her if she has mentioned Leeds to her mum and she usually says "yeah she'll have the money.." whenever. I feel more and more awkward about it. I just want it to be paid back. The thing is I have a feeling she hasn't told her Mum about it, I feel as though it's my fault because I was the one who suggested my mum could get the ticket and her mum could pay later, cos at the time we'd decided that we weren't going but I half thought last minute it would be really good if we could go, and at the time, she'd said that she'd told her mum she wasn't going and so she didn't have the money she'd saved. My mum hasn't been harring me for it, but she hasn't been in contact with my friend's mum about it either cos she said, she'd pay her when she's ready. I really hate bringing it up, it's really awkward and I feel like I'm being a *****. I don't know what do to.