Is it normal for the entrance of my vagina to be like tough texture or is it supposed to be smooth?

After puberty the vaginal lining thickens as an effect of estrogen stimulation. That allows the tissue to build up a thickness/toughness that is more tolerant of the mechanical trauma of intercourse. If you are concerned this is too much have this discussion with your doc at a regular visit.

Agree with Dr. Ferguson. Get HPV vaccine. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs.