Fat people get laid all the time. Old, young, doesn't really matter. Don't believe me? Go to Tesco in the evening and look at all the overweight dudes being dragged around the shop by their gf/wife.
But back when I was younger and living in Germany I saw a lot of 'bigger' females with black guys and asked my mum why that is and she said 'because they need the paperwork to stay here and those girls are more likely to be with them'
If you were getting 'laid' before University, then chances are you will continue to at University. If you have zero confidence due to being overweight, resulting in you not getting laid before going to University.. chances are you won't at university.