She wants me to sit buy her?

she wants me to sit buy her all the time or she comes to sit next to me when am with her we talk every day flirt etc. i have a feeling i am more than a friend to her but i don't really want to ask we spend time alone also not just when my friends are there. i want to know what other things i can look for separates me from being a friend and if she would ever tell me with me having to say any thing first.