If you find out that exercises in your workouts are too challenging, you can always change your fitness level using the Assistant.
Selecting a lower level can make the exercise easier to perform while still providing a challenge.
You can also evaluate your fitness level to get to know if your program is really suitable for you.
Sometimes, the app can offer you to rate the workout difficulty after it finishes (on Android devices). Having marked your workout as too difficult (if you tap on 5 twice), you will be proposed to lower your workout level.
Remember that progress takes time and consistency. It's okay to start with lower intensity levels and work your way up gradually. With consistent effort, you will slowly build strength and endurance and be able to tackle more challenging workouts.