Dental Implant After Braces?

A phrase we use here in the US, "haste makes waste", means rushing into things can lead to problems. Is there a reason the dentist wants to place the implant now? Perhaps timing the placement so integration is done when the braces come off? While that is a worthy goal, there may be some challenges to the orthodontics that are created by having an implant present.
It may not be a big issue, but I would wait.

As long as  there are no more teeth movement in the region of the missin tooth, it's ok to proceed with implant placement. But if there are any chances of further adjustment, then it's better to wait. Also, the orthodontic wire may have to be removed to allow implant placement easier, and then replaced when completed.

It is important to know the overall treatment plan. If the site for the implant will not be changed by the remaining 3 months of orthodontic treatment, then it probably is not a problem to place the implant now. Ask your dentist what are the pros and cons of placing the implant at this point in the treatment process.