I am 60years old and have come back to playing brass some 3 years ago. One issue I can't resolve is that my notes don't always start when I tongue and then when I have been playing for 30 mins, I develop a buzz which seems to be produced in the centre part of my embrochure. Sometimes if I have a break for a couple of weeks, I play better .....??? Any thoughts/ advice please? Am I too old to get any good?