Indoor cat outdoor

Chiquitita is 11 years old Burmese cat. She is has been indoor cat all of her life. She came to us about 7 years ago, after pedigree cat life. 

She doesn't go out of door, without us. Maybe just to first step.
But when we are out in upper garden, she comes out to deck, but not to grass. She likes to watch birds and bugs, but often run like hell on her heals back to indoors. 
I think she does not like world without roof. It's too big for small indoor cat like Chiqi.