Your x-ray shows that the plate and the screws are still intact in the right position. In some cases, it may take longer for callus to form, and the fracture to heal completely.
Of the two bones in the leg, tibia is the stronger bone that bears the maximum weight. Your fracture is in the smaller bone called fibula which anyway isn't too critical for bearing weight. Secondly, your plate and screws are all intact so it shouldn't be an issue if you start weight bearing.
Still, it is a matter of concern why it has taken three months for the fracture to heal. That's why I think its best to take detailed advice from experienced Orthopedic surgeons.
I can help you obtain a detailed medical advice from highly experienced Orthopedic surgeons so you are completely well informed about this. For that, I need some additional information about you that you could share by email. Unfortunately, I am not able to share my email address through the forum but if you request the website administrator, perhaps they will be able to share it with you.