I'm adjusted to both. I started off with the N64 when I was like, 2. But I didint play much, unless with my brother. Sometime before my 4th birthday I got more into the N64, I still didnt play as much as I did later on. Then we got a PS2 for christmas. So I sort of swpaped between each. Played MX unleashed on the PS2 before returning to the n64 and Mario Party 3. Then I continued swapping.
Since I grew up using both, I never had a problem. But I never look at the buttons once I know which is which. The rest comes naturally.