If you live in a cold weather climate and don't enjoy exercising out in the snow, you may have chosen to get a small breed so that you could both get your exercise inside. The Chihuahua is a charming, personable, loyal little dog who comes in a variety of colors, coat lengths, and shapes. The Chihuahua is an ancient breed that suffers few health problems and is intelligent as it is charming. Your Chihuahua puppy will readily learn potty training but during a cold winter, you may face a new problem. While your Chihuahua may be willing to go potty where you would like her to, she may not be willing to face the freezing temperatures outside. You can certainly potty train your Chihuahua in the winter, but be willing to make some compromises.
Chihuahuas weren't made for the cold. They come from Mexico, and their years becoming popular and changing shapes all over America have not made them much more cold-hardy. While long-haired Chihuahua have some advantage in the cold, their coats are single layered, not thick like the spitz type dogs bred for the snow. All Chihuahua must be protected from the cold even for short periods. Heavy fuzzy jackets that don't restrict her delicate throat and weather-proof booties for her feet can help keep your Chihuahua comfortable in the cold.
Whether your eventual goal is to have your Chihuahua go potty outside, or if you intend for her to use an indoor pad or litterbox all her life, it is best to train inside for some time in the winter before moving to outdoors training. Your Chihuahua puppy should know what she has to do, and not have to do it so often, before being asked to do it outside in the cold. In time you will develop a routine with your Chihuahua puppy, and it will be easy to know when she needs to go out and to keep the outside time to a minimum. If you decide that you would rather have her continue doing her business inside, she will always be small enough that it is not too much of a mess.