Should I date him or is it too risky?

About 2 months ago a friend of mine introduced me to a friend of his. I'm 17 and he's 21. I've been hanging out with him a good bit (not one-on-one hangouts, usually in a group of 3-5 people), and I'm started to really like him. I think that he might like me too. However, the friend that introduced us told me that he was abusive towards a girlfriend he had about 5 years ago in high school. My friend said that he has changed a lot since then and he doesn't really seem like the type to do something like that. So do you think I should date him and see how things go or do you think it's too risky to date someone who was once abusive? Please help, and thanks to everyone who does.