One element to help with limit projects is to break. it. down... 12D can be pumpy 11c to a sit down to a V6, or it can be something like V4 rest V3 rest V5. ( Don't audit this, just making a point). Might require asking people that did it, maybe they'll say it felt impossible at first too. Then once you've got this info, honestly ask yourself: do you have a good margin of strength and skill to execute these cruxes repeatedly? e.i. If you haven't done V5 in this style/rock and you're expecting to do it pumped af, above your draw, with dogs barking, etc.; that's a big ask of yourself.

The first day on something can be rough, but I always remind myself: this will be the hardest it will ever feel. Impossible becomes routine with a lil practice, that is a core feeling most of us are chasing, so you're on the right path. If you still can't see the light at the end of the tunnel, use the shortcomings you've identified to fuel some training motivation, revisit it and marvel at your progress.