This happened just a couple of months ago. I will give you a little bit of context first.
10 years back she moved in our next door flat. For the sake of the the story let’s call her S. My mom being a helpful woman helped her settle into our building quickly. From then onwards S and my mom developed a good friendship. I eventually met her and she was very nice towards me. Over the years we grew close and she treated me like her own son as she was single. I used to visit her flat often also sleepover there sometimes. As I grew older I started liking her more and more.
As I turned 16-17 I started fantasing about her. I knew it was wrong and didn’t act on it or told anyone. But whenever we used to hug I made sure it was a long hug. We also used to kiss each other on the lips (nothing sexual) and during our sleepover used to share the bed and cuddle. When I turned 18 I noticed that she too started flirting with me. She often used innuendos in our conversations. I liked that she flirted with me, but we never dared to go beyond that. This year on my birthday she invited me to her place and so I went.