Unless it changed since i was in, 20 years in the guard all have to be good years. You have to accumulate points per year. If short, that year don’t count and must be made up. I believe you must have 60 points per year (15 for AT; 4 per month for weekend duty). Also, you can ‘retire’ after 20 years but must wait until you’re of age (I think 60 y/o). I don’t know about Baby Guard, never heard of it. Someone else can comment on that. Also, if I am wrong on anything, pls correct me.
It’s 50 points a year for a good year.
And before you finish with the reserve or NG make sure you get a “20 Year Letter” stating you have 20 good years and are eligible for retirement which begins at age 60.