Extreme sensitivity and arousal during intercourse is not so unusual in partners that are not very experienced. You might try to spend more time in foreplay, leaving the stimulating areas untouched. Have in mind that what you think is too much sensitivity, might be quite normal. Even if the sensitivity is too big, it might make you feel uncomfortable during intercourse, but there is really no reason for it. You might want to try lubricants with anesthetics. Before trying these lubricants, check if you are allergic to the anesthetics.