Would this be sexual abuse?

When I was younger maybe around 9 or 10 my cousin would blackmail me into licking her clit. I would tell her that I didn't want to or something and she was like well I am going to tell our moms that you drink the whole 2 liter of drink. At the time I didn't know any better and I didn't want to get into trouble for drinking the drink. This happened for a good while. Some how our parents finally noticed but it was like it just got swept under the rug. I am now almost 30 and I am finally starting to realize something wasn't right. I still don't know if my mom knew that i blackmailed into doing it.