Good question.
What sort of budget do you have?
Are you prepaired to get finance for it? (if they allowd this)
How late a model car do you want?
I would keep the beetle a "dream car" at this stage. They are a great spring/summer car but impracticle for a young person.
The Mini cooper, fantastic car even the early models are still a great looking car in good condtion but id be looking for one of these newer models if i was you. These cars are still quite expensive to buy and maintain so i would give these a miss just now aswell.
I dont know alot about the mazda 3 but again if you can get something of late model, this would be good as i believe they have a "reliable history" as you dont want to have it at the mechanics all the time.
Now, the suzuki swift. I actually like these things and with some pin stripes and a few decals you could turn a humble swift into a "girly's car". Parts for these things are quite easy to get hold of and maintenance would be cheap. So out of the 4 cars you like this is the one id look at.
My advice would be to buy a late model as possible and have it checked out by an honest mechanic (does one exsist) before forking out your cash for the said car. Good luck with it, hope this has been of some help.
PS, Have you thought about joining an online car forum/club and doing a little research through them as to what people are driving and what they think of your fave 4 cars? Im the events rep for a car club here in NSW and members allways talk to each other about the pro's and con's of cars so this could be something eles to do before buying a car. Good luck.