Female tenor?

Hi I am just starting to learn to sing, just for fun. I am a 58 year old female. I find the tenor exercises easier, although my range is not very wide. But it's only with the tenor exercises that I can even hope to reach each end, and in fact the lower end of the tenor range is easy for me while the high part of the tenor range is very difficult. Should I be using the alto exercises because I am a woman and concentrating on moving my range higher, or can I stick to the tenor exercises? Is there such a thing as a female tenor? Or is it just voice deterioration due to age?

Great question! There are certainly female tenors, and it's true that most female voices do shift lower with age. My advice is to use the exercises you find most comfortable!