Always ask her first, “may I enter you?” Put one finger on her clitoris and keep it steady, delivering strokes she likes, then put more presence on your other hand. Focus on moving it slowly into her vagina, first with one finger, only a 1/4″ in. Go slowly! There is a lot of sensitive around the outside of her Introitus and outer lips. Maximize her pleasure by letting her really feel your fingers on the outside of her vaginal entrance before heading inside.
Try a “windshield wiper” stroke inside her to get her internally engorged.
Next alternate windshield wiper strokes with a rhythmic “come hither” stroke deeper in.
Finally, work the “balance point” between having your fingers near the entrance where she can feel surface stimulation well because of the rich network of nerves, and insider, where pressure feels better.