Answer:
Vegeta is 64
When he was first introduced in Dragonball Z, he was 29. When he arrived on earth, (1 year later) he was 30. In the Cell Sagas, (5 years later) he was 35. He trained in the Hyperbolic time Chamber 2 times, (each made him 1 year older) he is now 37 years old. In the Buu sagas, (7 years later) Vegeta is now 44 years old. In the end Dragonball Z. (which takes place 10 years later) he is 54. Dragonball GT takes place 10 years after the end of Dragonball Z