Josaphine - beware! Minis are very expensive to run and insure! The reason? Young, first-time drivers like you think a Mini will be a cheap lttle runabout. Consequently, Minis (especially owned by youngsters) are a far higher insurance risk and the premiums will reflect that.
Secondly - I've owned three Minis by default (first wife and her daughter both had one and my sister-in-law who gave it to us). All the parts are surprisingly expensive for such as standard little car. In fact, the only reasonable costs to owning a Mini is low fuel consumption.
I really wouldn't recommend you buy a Mini Jo. It will cost you a bomb. Does someone in your family know about cars? What about your Dad? They usually sort cars out for their kids - it's what Dad's are for! Perhaps a VW. I have a 1984 Golf and the insurance is £146 per year (about £2.80 per week). OK - I'm 48 with 30 years driving and a clean licence, but a VW (not a GTi!) may be cheaper for you.