I would like to eagerly encourage any man to be an altar server, regardless of age. Your physical ability, and speaking ability is all that matters.
If you feel you have a calling, even if you've never done it before, please do not hesitate to ask permission of the priest. I'm sure he will be delighted. Even if he isn't, that could be a sign of testing you, and your patience and perseverance will be a great consolation for the priest.
Your example for the boys will be an enormous grace for them.
Today our 40-year old priest was served by a 73-year old man with a hearing aid, who stuttered at one of the prayers (May the Lord receive this sacrifice at your hands... I don't recall the Latin at this moment HAHA) and the priest reminded him, quietly. It was a moment of grace for me, to hear that happen. So don't be afraid of making a mistake, because the people assisting at Mass will be edified by how the priest deals with it, and God knows your heart, so fear not!!