A tin whistle is an Irish instrument. It has 6 holes, and it is played by blowing through the mouthpiece and convering and opening the holes with the fingers.
Well tin whistle today are now made with nickel,brass,silver,or wood. It's not made with tin. The tin whistle is named so because before it was made with tin-plated steel.
To play fast, you often should start by practicing the piece slowly. Using a metronome can help. Then gradual practice it faster and faster, but only as fast as you can play it without messing up too...