Answer to your question title:
Well. Your intention was not of lying, but to ride the roller-coaster. So, you presented the fact (your height) in a way best known to you. So, you spoke an honest lie.
An honest lie or confabulation according to wiki article is,
An honest lie or (confabulation) can be identified by verbal statements or actions that inaccurately describe history, background, and present situations. There is generally no intent to misinform and the individual is unaware that their information is false. Because of this, it is not technically a lie at all since by definition, there must be an intent to deceive for the statement to be considered a lie.
Confabulation is a memory error defined as the production of fabricated, distorted, or misinterpreted memories about oneself or the world, without the conscious intention to deceive.
Answer based on your explanation:
The example that you provided is of a trivial nature. Such lies are not culpable.
A fib is a lie that is easy to forgive due to its subject being a trivial matter; for example, a child may tell a fib by claiming that the family dog broke a household vase, when the child was actually the one who broke it.
NOTE to OP: Please update your example. So, it will be easy to select appropriate type of lie.