Whether a fast swing tempo is the correct swing tempo for a senior golfer really depends upon the individual.
If you look at all of the leading golf professionals competing on today’s US and European Tours, you will notice that they all have different swing tempos. If you watch players such as Tiger Woods or Sergio Garcia, you will see that they play shots with a very fast swing tempo. However, watching players such as Ernie Els or Fred Couples you will see a much slower swing tempo. There is no one correct tempo to swing your golf club with. It really depends upon you as an individual and the tempo that you are comfortable with.
A good way to notice what tempo you are comfortable with is to notice the pace that you walk at. Are you someone who likes to stride out ahead at a very fast marching pace. Or are you someone who takes it easier, sauntering along? This will help you notice you own natural rhythm for doing things. If you like to 'march', then try a faster swing tempo. If you prefer to walk slowly then a slower swing tempo will work well for your golf swing.
Whether you try a fast or slower swing tempo though, the key is to keep it constant. Consider two pieces of music, one with a really fast beat and the other with a slow beat. They both have rhythm but a different rhythm. The key though is that rhythm remains constant and this is true during your golf swing.
To help you with this, try the following. Work on counting as you swing. To keep a constant tempo, make sure you keep the pace that you say the numbers constant. You should be able to say 1, 2, 3 on your backswing, with 1 starting your swing, 2 being said when you are half way back and 3 being said at the top of your backswing. Then say 4 and this should be said as you connect with the ball.
But remember work on saying the numbers with a good constant pace and get your swing positions to fit the numbers as they are said – not the other way round!