I have a lot of extracurricular activities but I don't know which ones to include in order to stay within the character limit?

It's always best to make a list or a table of all your extracurricular activities, as well as writing what skills you've developed or learnt through each activity or experience. E.g. Being a captain of hockey team would develop your leadership, teamwork and communication skills. This will allow you be to more aware of how to use those extracurriculars to your advantage in your personal statement. This also means that during your witing process, you're selecting experiences that are well varied. For example, so that not all your extracurriculars are about improving your leadership skills. Lastly, it is important to consider the course you're applying to. For instance, if you are applying to study medicine and you have done some volunteer work at a charity, it would be beneficial to include that experience in your personal statement as you could elaborate on the characteristics involved such as altrusim, dedication, compassion, etc.