There is nothing for you to be reported for other than to your director. It could be viewed as an ethics or confidentiality breach. To the parent, it probably felt like a huge breach of trust and a privacy invasion.
A simple apology and maybe taking a couple of training classes on confidentiality and mandated reporter's roles and responsibilities would be all that most directors would ask. We take them annually for a reason.
IMHO, you were simply overreaching. Human sexuality is something kids giggle and talk about, especially since Valentine's Day was last month. It is normal. Unless you see something that really makes you suspect abuse, then report.
At no time are we allowed to question children to support our suspicions. That is the professional's job, all we can do is ruin or contaminate an investigation by probing. We should correct the immediate behavior, continue on with our day, then report if we have concerns.