Does anyone know how long my wheaton will be in heat the first time? Discussions

My wheaton is about 8 months old and in heat for the first time. How long will it last?

It is hard to tell with a first heat. A season should last three weeks from the first show of colour, but I have had bitches that would still stand for a male into their fourth week. I have also had bitches that had a false start, a short gap, and would then come into season properly. With a maiden, I would bank on keeping her away from males for about a month, but she could have read the textbook, and be quite normal.
Keep a close eye her back end, (swab with cotton wool or white tissue if she keeps herself clean), and be extra careful when the discharge colour begins to fade, and her vulva starts to relax. When her vulva shrinks down again, (it is unlikely to completely return to its juvenile size), you could test her ON THE LEAD with other dogs. If there is any flirtiness, or undue interest from a male, give it another week.