Yes, I think you should, just mention, that you are just making sure she still understands, you are in no way encouraging her to have sex, because it is very emotion for someone as young as her, but if she is, to make sure, they are both being careful with their protection.
Also remind her that this is also something neither of them should share with others. This is not a subject that is shared. It is very private.
I used to speak a lot with our daughter about teen choices and consequences. This included, drugs, alcohol, illegal activities and sex.
When we heard about kids at her school, or in our area, that had gotten into trouble, we spoke about why, what and how this was now going to affect this persons future. How must they feel? What their families must feel. How would they be able to get past this?
We spoke about the girls and their boyfriends that got pregnant and how everything changed over night. What would they need to do to care for this child? It seemed like these kids aged 10 yrs in just a few days.
There was a group of popular guys at one high school that had a huge party and a girl died because no one realized how I'll she had become fom the alcohol. These guys were 17 and 18 and so they were charged with providing alcohol to a minor. They both lost their college scholarships.
And so you want your daughter to feel she can share anything. If she needs protection, an excuse, or a mom to speak with, you are always going to be there.