Life long roadgeek here, though I didn't learn about the actual term until a few years ago. And I still prefer to call myself a "highway enthuasist".
At the age of 2, I taught myself to read by reading highway signs (it was the early 60s, so there weren't any graphic signs yet). And I was drawing roads (with signs) on paper at age 4, and making paper signs and mounting them on overhead supports made from Ideal Super City pieces at the age of 7.
By age 8, I was the only person in the family my father would trust (apart from himself) with the road maps when we went on trips. And what trips they were. Some of my earliest memories of those days include crossing the then newly-opened second span of the Deleware Memorial Bridge, driving through the construction zones for building the original "dual-dual" roadways on the New Jersey Turnpike, and later on - the widening of the Wilbur Cross Highway (now I-84) between Hartford and Sturbridge.