Matt is an extremely powerful Super Saiyan. When he fought and defeated Zeel, it was found that in 20 years, he would become the next Super Saiyan 5!
Matt only lived to be 29 because he died when he tried to go SSJ3.
Matt was only 14 when he killed Zeel.
Matt never got to go SSJ5 or even SSJ4 because he died when he tried to go SSJ3.
The reason Matt couldn't go SSJ3 is unknown.
Matt is the desendent of Future Trunks.