From a previous question, I saw that he was in his late teens or early twenties but I want to know a little more factual details. The comics don't even help.
How old is he?
Lucus Till, who plays Havoc, was in his early twenties while filming X-men: First Class.
I would argue that makes this version of the character no less than 18 and no more than 25.
The comics will be of little help as:
So all we have to go by is the actors age, and the character's apparent age of 18-25.