help me please !

C
So I would like to see my friend Jane on Saturday. My mum doesn't like Jane because of what she has heard about her, my mum thinks that I'll be into trouble if I'm with her. If my mum trusts me then why won't she let me go with her. My question is, how can I get my mum to let me see her? I haven't seen her since December and I'm really really missing her