Wellesley’s size, historical legacy (women’s education), social atmosphere (no sororities) and proximity to Boston all appeal to you. Based on your criteria, it appears to be the school to beat in this comparison.
In favor of Cornell, it’s highly noted for strength (both in range and depth) in biological sciences. However, it would not offer you an edge in premed planning over your other choices. Also, at CALS it seems important to be comfortable with your intended major. The 22 majors it offers are substantially fewer than you would have available to you at Wellesley or Bowdoin.