Hey Aisha,

If you have filled any college in second preference and other student as you stated have filled it on the first preference, the marks obtained will play a very crucial role in the allotment of college as if the marks difference between you and the other student is very far apart then definitely you will  have great chance to get both the college but if the marks difference is less like for 10- 20 marks then she might also get that college and if she is getting than college you will be definitely allotted that college as you have more marks than that of her.

But she will have a chance to get in as the institution is her 1st choice and you have it as a option and I would suggest that you focus on your first choice.