Ask her out or turn my back?

ok so theres this girl at work that ive been working with just under a year now and back in september I asked her to my yr 12 formal/farewell. At the time we only barely spoke and i was quite keen on her. Were both quite shy, shes never been in a relationship and her parents are very firm. When i asked her she said she couldnt come because of her parents and also because we barely knew eachoother. We didnt speak or see eachother till January because of the HSC and when we did see eachother, exchanged very few words. I kept my distance and sort of avoided her because i thought she didnt want to talk to me. We are now starting to talk again slowly slowly and I have feelings for her. Now do i apologise to her for being a ******** and avoiding her all this time and explain the reason why I didnt talk to her before i ask her out? Or not even bother with her?