Not Lauren here but maybe I can help? These workouts are hard. I thought I was fit, I did TA for 5 yrs, DB, you name it, but my arse has been whipped and no I am not "teeny-tiny" 🙄.
What I would suggest is to try the short sculpting workouts to get a feel for it. Lauren suggests her post partum and the 55 minute getting started workout.
If these are still hard, do what you can. That's what I do in each workout. If you could do it all in one shot, you'd get bored. I have to remind myself that every time. Everyone gets discouraged.
Do what you can, then jump back in. If you've had enough, then doa little more of the workout next time. Also, don't be afraid to modify. No shame in dropping a knee or keeping it low impact. Lower the weights or don't use ankle weights. March in place, side step, jump when you can .
If something hurts, don't do it. Pretend that exercise doesn't exist for now and FF past it.
I hope this helps. Lauren, I hope I didn't over step!