I Shouldn't Have Done It

Since I remember, my neighbor Grace, took care of me since I was a child.
My parents always come at night from the work and she always watch out for me since pre school.
When I reached puberty and started getting erections for no reason, I found myself jerking off on her toilet quite often and feeling ashamed close to her after it.
She never said anything, but now I understand that she probably knew what I was doing.
One day, she fell asleep (like in so many other occasions) watching TV on the couch and was wearing a very short skirt.
I was laying down on the floor and without any intention, noticed that she wasn't wearing any underwear. Her legs were slightly open and by the very first time I saw her hairy pussy. In fact the very first pussy in my life. ( Yes, I know she was old)
Nervous as hell, I got closer to take a good look at it.
My body was shaking with a mix of excitement and fear, because at this point I started to masturbate and cum in seconds on my hand. I quickly grabbed a tissue from the box that was on the table and without hesitation started to jerk off again. In a moment of courage and whatever was going on my head, very slowly open her legs a little bit more and take a good look at her pussy.
I was so excited that I got up and continued masturbating close to her face until I finally cum.
With all the excitement, I didn't notice that I ended up cumming on her clothes.
As I was cleaning myself on the toilet, she knocked on the door and simply asked: What have you done that my blouse is wet?
I just freezed...
And again she asked: what are you doing there with the water running?
I was been caught and have no place to run or any good excuse for what I just have done...
I opened the door with my head down and so ashamed that I just wished that I never done what I have done.
She looked at me while entering the toilet and didn't say a word.
I was seated on the kitchen wondering how my parents would react when she tells them what have happened when she comes back and asked me again what happened when she was sleeping.
Knowing that I have no escape, I told her that I unintentionally see her bush (Yeah, I told her a lighter version) and that I got so excited that I just jerked right there and ended up getting my cum on her clothes and I never wanted that to happen.
She keeps staring at me for a minute and not a single word got out of her mouth.
Because I have no way to get out of it, I said I was very, very sorry for my behavior and I shouldn't never done such thing and begged her to not say anything about it to my parents.
She continues just staring at me (I was crying already) and says: I'm not going to talk about this to your parents, and I'm also not going to punish you or stop taking care of you, but, I hope that you understand that what you did is very serious and I'm truly disappointed with you in ways that I can't find the words.
I know that you haven't told me the story correctly, because I wake up when you opened my legs and see you cum close to my face.
It's perfectly normal for a boy with your age to masturbate. Just because I was sleeping and not wearing underwear, doesn't mean that I have to wake up with your dick on my face. Please, don't do it anymore and I forgive you this time.

I didn't masturbated for almost 5 months after that and now looking back at what I did, I feel shame for what I did on that day. It should never have happened...