Use your common-sense. Try to please God. If you are doing that, be quite confident, and do not worry.

5. Things you must not worry about
I have spoken straight out about the seriousness of impure thoughts and words and deeds, because you are old enough to understand it.

But here are one or two things that need not worry you.

   (1) Soon, within a year or two, you will find that blood will come from this opening of your body, and you may feel head-achy and sick for a day or two. It may even happen quite suddenly, and frighten you. But there is nothing to be afraid of, and nothing to worry about. When it happens, come straight to me, and I'll show you what to do. You see, it is quite natural, and only shows that you are grown up and healthy. This blood has in it the tiny egg we talked about. Your body will soon begin to make one every month. But until you get married, you won't need them, so the body gets rid of them this way. You call it your 'monthly period'. Come to me as soon as it happens, won't you? I wanted to tell you about it before it happens, so you won't get frightened

   (2) Another thing. As you get older, you will find yourself more and more attracted to boys. That is quite natural. God makes us like that, or else men and women would never fall in love and get married. God put the attraction in us, and it is good; but at the same time, we have to control it. Perhaps, at school, you will hear the other girls joking about boys and talking about them in a silly sort of way; don't join in any talk like that.

These feelings and attractions are natural, and shouldn't worry you. But at the same time, you must be very careful about purity. It is a great virtue, and very pleasing to God and to Our Lady. The best way to keep pure is to be very careful about modesty, which makes us fear to do anything