First of all- welcome back :-) It is wonderful when people take breaks and then come back to their practice, as usually soon after that they feel really good and it’s lovely to see them flourish!
As for your question- I would suggest going back to basics as it is ALWAYS a good idea to remind yourself of the technique points- how to do the postures well and what cues/imagery help you get the best results. When you feel that your body is handling the challenges well and you remember the postures and sequences without having to look at the screen too much, allow yourself to progress on to more challenging classes until you gradually return to the level at which you have practiced before.
The process described above will allow you to build up your fitness level gradually and also to notice what has changed in your body since you last practiced regularly. Our bodies are very dynamic and they constantly change for better and worse. If you start at a level that is not appropriate to you, your body will have to prioritise “surviving” the class and you won’t have the chance to observe and correct yourself. With a bit of patience, I am sure you will discover that your body remembers how to move and will adapt itself before long!
Enjoy the classes.