How to approach teacher? someone please help me!?

-Ok. here are some more details. I was in grade 10 last year, and the co-ordinator was really nice. I did some naughty things last year though about she was involved in one, so i didn't think she liked me much. and i was rude last year to her once too. Anyway, by the end of the year i had got my act together. this year, i have been much better. I am in year 11, so no co-ordinator. But this teacher has come back from long service leave. And well. she is really nice, and some stuff has been happening recently.. it's kind of to do with school.. and i'd like to talk to her about it. I feel so awkward and embarassed though, i do not know how to approach her. one of my year 10 friends told me how she said to THEM that they can talk to her about anything, etc etc. but that's year 10s. anyway, i can't just go into her office and be like oh HAAAAAY lets talk?!!!? she is my sport teacher but she's only taught me once, and only for 4 weeks more she will. help! how do i approach her, thankyou