I have a MacBook Air 2011 I have Big Sur 11.7.10 can I install macOS12.0

High Sierra is the end of the line for the Mid 2011 MacBook Airs.

If you bring up About This Mac in the Apple () menu, what does it say for the model name and year / time of year? (No serial numbers, please.)

Since your computer's running Big Sur, it's not a 2011 model; Monterey requires a MacBook Air to be an early 2015 or newer one.

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