Well, with 27 years you should be able to act like an adult and not like a child.
Your mother doesn’t like the idea that you grow up and be independent, so she prefers to make you feel small as this way she makes sure that you still depend emotionally on her.
What can you do? Well, in the first place, act like an adult and speak like an adult. You have to tell your mother that you are old enough to make your own decisions and stand on your own feet.
In the case she doesn’t understand all you can do is ignore what she says and say to the people kindly that they have to try to understand your moms behaviour, because she is old now and don’t understand how life is nowadays…
She will feel embarrassed and modify her strange behaviour.
Sometimes mothers don’t want their children to grow up and have a personal life, because all their life ideology is based on their children.
Once the children grow up they do not really know what to do with their life, they don´t have any hobbies and don´t know how to use all this free time.
So controlling the life of their grown up children converts into their only spare time activity.
It´s difficult for these kind of women as well, but you will have to put your foot down, as this situation doesn´t improve with the time and on the long run it will make everybody unhappy.
Maybe trying to find an activity for mom would be a good start.
As soon as she has something to do, which occupies her time and mind, she will start to loose interest in going behind you and controlling your life.
Look for activities in your area where people of her age go and take her there.
Maybe a nice hobby like painting, drawing?? Sports? Excursions with people of her age???
If this doesn’t help all you can do is live your own life and close your ears to your mothers complaining and take it like a joke in front of others.
She will get board with the time.