If your image appears to be erect, no matter how far you stand from a mirror, the mirror is likely to be :

Both plane mirrors and convex mirrors always produce erect (virtual) images of objects regardless of the distance at which the object is placed. A plane mirror produces an erect image of the same size, while a convex mirror produces a diminished erect image. Concave mirrors, on the other hand, produce inverted real images for most object positions (only producing erect virtual images when the object is within the focal length). Therefore, if the image appears erect at all distances, the mirror could be either plane or convex.