Adjust to wearing a mask by starting off with fun things – science experiments, cooking or just as a game. Look at some fictional or computer game characters who wear masks.
Try wearing a few different types of masks or face coverings before you have to wear one for real, and practise wearing one and "building up" your tolerance. There are different shapes and types of material and you might find some more comfortable than others. Cloth masks may be better than paper ones and have "edging" that is softer and may be more tolerable.
Put your mask in your pocket/bag/purse at the start of the day, or place it somewhere obvious so you don't forget to take it with you. Make it a familiar and comfortable item rather than something awkward and different.