Guilt and depression. Want to die. help!

I am 21 yrs male.i grew up without exposure only with my sister and mother.i was 14 when I was sexually attracted to my sister who was 13. I don't know how it started but I started to touch my sister when we were playing and all of a sudden started to touch her in her sleep.i would touch her body inside her dress when she was sleeping and did it a few times...but I stopped after that...and all of a sudden did it once or twice after 2 years when we had to share the same room..but I was never guilty and I had great affection towards my sister and was very protective of her..I cannot believe that I did it.i had great love for my sister and still do.offlate I have been suffering from severe guilt and let the issue to the notice of my mother sister.i did not disclose the incidents .they were not mad at me but consoled me.i wanted to die because of the guilt as I was not matured at that time...the image of touching my sister inside her dress is killing me...I feel guilty and want to die.help