An invitation can be answered in more than one way. This page offers a place to compare choices in light of your energy and what matters to you, without assuming that attending is required.
The four options are going fully, going briefly, going with a plan or declining. Compare possible gains, costs, energy afterward and what you would need, then write why a choice fits and what you might say.
Optional and private. Any of the four is a fair answer, and you can change your mind later. Choosing what fits your energy is not rude or weak.
