Handjob from very unexpected girl

Well I was helping a girl of 19 with a wall being built , she was always teasing this old man I am of late 40s with her short dresses , low tops showing her medium sized pert boobs , to be blunt she is a little odd and not bright at all , but also very perverted and shy . She said as I was older she would like to get to know how to please boys - especially some lad she fancies but hasn't done anything due to low confidence in making boy come. She explained I was too old to think about sex but would I be happy for her to wank me off as she hasn't done it and wanted to wank her new boy off if he goes with her. Well of course even though I am shy myself .
So we ended up on her bed , she said I can touch her boobs but do not touch her fanny (as in pussy if US) So okay , I started touching her , she wasn't too happy and said just lie back , I was already erect when she saw it and she went a little red and giggly , she got my tool out as she went shaky and I was embarrassed but what the hell , she played with it and started doing a damn good wanking action , I groaned very early , she said are you gonna come ? I said soon ! she lifted her dress up and it got me grunting , she said that good? YES!!! She said as she wanking faster , does it shoot far ? I said can do . She went fast and my belly was going up and down - having a good fat belly it was very apparent I was having orgasm , to finally I let out 2 huge grunts and it shot and hit my cheek and other shoot hit her pillow , She jumped as it shot out and her mouth was gaping open as she let a big laugh out , however she was disgusted it hit her pillow case and threw it , called me dirty old man and told me to go ..... never seen her again but what a quick great 10 minutes !!!!!!!!!!!!!!!!!!!