I go to yoga every week, it's a class which focuses on the relation aspect of yoga (so lots of lying on our mats) - I've been going for just over a year and I enjoy it, it's an hour and a half during the week when I allow myself to completely relax. Hope you enjoy it Linda.
I guess it comes down to how good your teacher is - if you are doing it from a DVD then you may well be doing it completely wrong, but if you've got a small class and a good teacher then he/she should be watching out for you doing anything incorrectly which could cause damage. The number of people I know who have knee damage from jogging/running - and that's meant to be good for you
I love yoga. Not been for a while but used to go twice a week for 2 two hour sessions. My teacher is excellent and ensures we get plenty of time to get the poses just right to avoid strain or damage. There are certain things I am unable to do now due to Achilles injuries but still enjoy it. It is wonderful for relaxation and sleep but takes a while to totally wind down in class amongst others. You do learn to block everything out which is lovely. I do some at home now to get back to a stage I feel I can go back to classes and feel like I'm not a beginner again
I did tai chi and think it is great. Good to start exercise if you are not used to doing too much. I do both yoga and pilates but believe you need a good teacher for both at the beginning to get the positions and alignment correct.
Absolutely need a good teacher for anything, yoga or Pilates. I've done both but prefer yoga and was told by my first teacher that all yoga teachers teach different poses and classes can be different, she is so right. Some classes can be very fast so avoid vinyasa flow to begin with, yin yoga is where you hold positions for minutes on end and if muscles are tight it might not be good for you. Restorative yoga I find is similar and although the name makes it sound easy, I didn't find it so. I was told that ALL yoga is Hatha yoga. I recommend it to everyone as it's good for your body and your mind and wanted to learn to be a teacher but found it was too much at the time so am back to practicing. Give it a go!