Hello! We had our hearts checked 5.5 months ago and found that we have…

Hello! We had our hearts checked 5.5 months ago and found that we have an open oval window on our heart (one cardiac channel is not closed). Has anyone else experienced this? At what age did it close? And while it was closed, how did the child behave? My head sweats profusely and I often get sick with the flu? Please tell me your experience.