Plumie on right is one year old. During winter, I kept it in garage as bare root. Plumie on left I bought last week. Is it typical that they would be same size?

Lisa these both appear to be rooted cuttings so yes, it is perfectly normal for them to be the same size. It could also be that one is a more compact grower than the other. Age doesn't have all that much to do with size with Plumeria!