Here’s a very good reason not to lie: if you don’t honestly have the credentials to get into a particular school, and you are accepted there (based on the false premise that you are a high achiever) you could very likely find yourself struggling and unhappy at the school. Admissions folks know who is a likely to be a good fit for their college and if you get there and are surrounded by high-achieving, honest students who juggled a lot of extracurricular activities with their academics, you are not going to be comfortable. Put all this effort into doing your best and it will work out for you.