Ease into performing doable movements that are enjoyable for 20 minutes, any time of the day you choose. Just because you are not in pain, doesn’t mean your body isn’t benefitting from each purposeful exercise.
As you progress from a modified exercise to an advanced form, or increase weight, you may feel an unfamiliar muscle in your body the next day. This is probably because you have never/rarely used that muscle before.
Enjoy the benefits of not only looking more fit, but also being more fit; everyday tasks, like carrying children or grocery bags, will become more doable over time.