Obviously, the longer you can wait the better.
There is another aspect to striping paint to consider, depending on how much of a perfectionist you are. Tape thickness. The thicker the tape, the thicker the ridge will be, and the more obvious the raised edge is. 3M makes a series of "Fine Line" tapes for this purpose. There are also vinyl based tapes that stretch to curves better, and easy release tapes for recent coatings as you describe. If you have painted brick or concrete, the vinyl tape will conform far better. I always figure at least 30 days for a paint to fully cure. Do not underestimate the ability of fresh paint to come off with masking tape, especially cheap tapes or those left on for several days.
The easy release tapes won't give as crisp an edge, and have zero stretch. They do release easy if they don't get UV exposure. DO NOT leave tapes on in the sun for more than a few hours, unless it is specifically an outdoor UV rated tape. The yellow tape practically melts before you eyes in the sun.
After applying, run your finger along the edges of the tape to help seal the edge.
It is also important to time the tape pulling correctly. Too soon, and you can tear the new paint film. Try a little at a time initially, and go slow. If the paint tears, come back tomorrow. The angle at which you pull is also a factor.
2 coats max on a length of tape unless you want both a thick edge and tearing. Some guys I know will do 3-5 coats on a tape, and then razor blade the edge. Each to his own, but that takes some skills to do right, and you are leaving a path for moisture to get under the paint.
These days you can spend $30 on just a single roll of masking tape, but if it solves your problem, it's worth it. Some of this is a little overkill for a garage indoors in dim light, but hey, you asked.