I still don't know what it means

When I was about 4 or 5 I underwent some sexual trauma at the hands of a family member. I carry a lot of shame with me. No one in my family knows about it. I'm 21 years old now and I just now started telling my very close friends about it. Here's what happened. I was staying with my aunt for the weekend and she left her son (my cousin) to watch me. He was 12 or 13 at the time. After my aunt had left he invited his friend over (someone who is till a friend of the family and who I have to see every once in a while). We were in an upstairs room and we were all three sitting on the floor with the dog. I don't remember pieces of this probably because I was so young but also because I have spent a lot of time trying to block this specific memory out of my mind. I don't remember how this came up or why they felt like this would be funny but my cousin and his friend forced me to touch the dog... inappropriately. I was a young child with absolutely no understanding of any of this at all. I remember not wanting to and they pressured me into doing it. I remember them laughing. After that, the next thing I remember is that I was sitting alone in my Aunt's room and my cousin approached me and asked me to touch him. He said "please touch me" and he was holding the waistband of this pants away from himself and looking down into his pants. I remember saying no but I don't remember anything after that. I think that there might be more traumatic things that happened after that point but I do not remember at all and I don't know what to do with all of this... A lot of the time I wonder is this counts as sexual trauma...? I have a lot of difficulty because I have a feeling that my cousin was molested by my Aunt's partner and that might be why he displayed that sort of behavior. I have trouble feeling angry towards him for what happened because he was also a kid. It all leaves me feeling really uncomfortable and confused. I think the hardest part for me is what I don't remember. I do not know what happened at all and I wish that I did so I could figure out some sort of way to move on. From that point until recently, I pretended like everything is completely normal between me and my cousin. I carry so much shame about what happened that I find it really difficult to imagine myself every telling my family because I think it would destroy everyone. Does this mean that I'm a survivor of incest?