I think you answered your own question: Don’t quit what you’re doing altogether, and don’t go for it.
I don’t know the specifics of the plan, but if you’re used to a higher workload, then adjust it with the end in mind. Don’t do as much as possible; that’s self-defeating because it’s unsustainable. But have a look at the later weeks of the plan. If they don’t seem like a big, tiring workload, then increase the prescriptions accordingly.
I suspect that the plan is built to be conservative in the beginning and then more and more challenging without overdoing it. Pay attention to the proportions of different durations and intensities. Adjust them as much as you can safely tolerate.
It sounds like you know what it’s like by doing too much too soon. So give yourself a margin of error with any changes.
This all probably sounds pretty vague, but it’s hard to be specific without knowing more of your training history.