Do you think i`m too skinny at 5'2" and 100 lb?

How about 112 pounds. A healthier weight to aim for, and still be considered thin (body mass index of 20), would be about 112 pounds. Fortified milk shakes or smoothies, along with three balanced meals daily and snacking as desired, should help you achieve this goal. Continue to exercise moderately to keep the body toned.