Feeling ashamed of one's past

Q: I am really worried about something which I did 1-2 year ago. I was 16 years old and sexted with a married woman. She sent me a photo of her breasts twice. I felt so guilty and sick of myself and cut all contact with her. I am ashamed of what I did. My imaan wasn't that strong back then. I am a born muslim and I just remembred about it today. I think first time was one night in the holy month of Ramazan and second time later. What should I do? Will Allah Ta'ala forgive me for my shamefull sin? 

Betting

Q: Is trading halal? Like the website I am using is IQ Option. Where you bet the price on 4th decimal of the rate.