[jjaelovesenglish]

Don't worry about it mama. Girls tend to be somewhat more advanced at this age and write all kinds of mushy stuff where boys tend to laugh it off. I used to teach middle school and it is a very akward age. No explict sexual connotations in that note, just puppy love stuff. Not to worry.
If you are worried, check his pockets from time to time, or have hubby have that talk with him.
Good luck and hang in there, the road is about to get much rockier.