Is it normal to see your cousin naked

me and my sister used to have a bunk i am currently 23 and i still remember this my sister invited over 4 of our cousins(they were all 14 i was 15 sis was 17)when one of my cousins was getting out of the shower i saw her nice half grown tits it kinda turned me on but later that night she came to my room woke me up by sucking me off.it continued for about 2 maybe 3 years we both saw eachother naked one night she came in the room and said to buttf**k her so of course i said yes what 17 year old boy would not say yes to a nice assed girl then it ended when i moved out.