Hype wears off by week two. The alarm clock is still there in week ten.

Motivation is a starting fuel and it is not designed to last. The first two weeks of anything run on novelty and on telling people about it, and both wear out on the same schedule. What is left after that is the unglamorous machinery: the time you set, the kit by the door, the person expecting you. Whether it survives is decided there.

Assume the enthusiasm will go, and build for the version of you who is not feeling it. Make the first step small enough to do on a bad day. Attach it to something you already do without deciding, like the walk home or the kettle.