I would say that snake is nowhere near a year old. How much did she weigh when you got her? Pet stores usually have very little information about the snakes they have and they usually dont know what ehy are talking about. (My friend was sold a red tailed boa and they told her it would only grow to 3 feet)

If by fuzzies, do you mean mice? at 100g she should be on at least rat fuzzies. Youre going to want to get her on rats asap because when she is older, youll probably have trouble convincing her to eat them. Also, rats will make her gain more weight.