Congrats phiphika1453!
I have to agree with the docs here. I have known many women older than your wife who have had a tubal and have regretted their decision. Especially since there are many very effective forms of birth control that allow you to change your mind and are much less invasive.
Mirena is an IUD that releases a hormone,levonorgestrel, which is the same med that is in Plan B or morning after pill. It is placed in the uterus(in the doctors office and takes about 10 minutes) and stays there for 5 years. Its easy to have placed and even easier to have removed. Minimal side effects from the IUD, most likely periods will eventually stop and almost as effective as a tubal.
I really have not heard many negatives to it, but there are always considerations.
Google
Mirena IUD and there is quite a bit of info out there.
Vasectomy is also another effective means of birth control and its reversible, but also invasive.