The story of [M] and my Co-worker [F] [MF]

To give you guys a little background, I’m 34 year old and from Austria. Therefore, my native language is not English but German. So please don’t be too harsh on my grammar or typos. I do my best and am very sorry for every mistake you will find. 

Where should I start? I guess at the beginning.

I work for a client in IT as a Software developer. In October 2017, a new girl started as a frontend developer. Somehow a cute redhead but nothing to special. Naturally, we had a lot to talk about, since we need to work together. Quickly a bit of a friendship evolved, which is always nice. We started to spend breaks with each other and had a lot more to discuss than work. 
X-Mas party came and we got even closer. We danced and drank a lot we touched a lot, just gentle touches to the back of the hand, or shoulder or the arm nothing sexually really. We spent the night together until 5 am. That night was for me also the first night; I realized how hot she is. I “saw” her in her green dress for the first time, not as co-worker, but as a very sexy Lady. She displayed her A cup in such a perfect way and presented her unbelievable sexy curvy ass like nothing else.