This plan you have, of monitoring every move your 13 year old daughter makes could definitely come back to bite you in the butt.
My parents did the same thing to me from the time I was 12 to the day I turned 18. Of course, they thought they were justified because my sister (5 years older) got pregnant when she was 16. Because you know, all kids are the same... NOT.
I missed out on too many things. My friends stopped inviting me to go along with them, anywhere, because they hated that my dad had to come every time. He snored during movies, he yelled at the mall, he wouldn't let me leave the bleachers at the football games... when they would go walk around during half-time, I was left in the bleachers with my dad - often times, they didn't come back.
I ran out of parent-tolerant friends by 10th grade.
Then, when a new boy in my grade moved in 3 houses down, I started to hang out with him. My parents met his and actually liked and trusted them... Obviously they didn't get to know them very well...
We became great friends and I spent any free time they would give me at his house, in his bedroom with the door shut, listening to Pink Floyd and smoking weed, with the full knowledge and permission of his parents. I did that for 3 years because they wouldn't let me do anything else.
I even missed my prom because they couldn't be there.
I guess what I'm trying to say is take a step back and look at your daughter.
I never had ANY interest in sex during high school, simply because of my sister, but my parents never asked me or gave me the chance to show them that.
Don't sell her short - TALK to her about how you feel and about how she feels. Do NOT overlook her feelings and what she has to say.
The experience you have in high school will follow you your whole life. If you've raised her to do what is right and you know that SHE can be trusted then you need to let go.
You have to give her a chance to prove herself, before she gets to the point where she just wants to rebel.