At Google: L3 is a new graduate L4 is mid level (an engineer who you can generally trust to complete the tasks they're assigned) L5 is Senior (who owns/shape

At Google: L3 is a new graduate L4 is mid level (an engineer who you can generally trust to complete the tasks they're assigned) L5 is Senior (who owns/shapes the direction of the team) L6 is Staff (who has to see upcoming problems and shape efforts across the organization) L7 shapes a product L8 shapes a division L9 shapes an industry It's very possible that a 24 year old could become an L5 with a typical path: college 18-21, straight to Google for 3 years on the same team and becoming one of the main contributors on the team. Considering that Google grew its headcount by over 50% between 2020 and 2022, there could be plenty of mid level engineers joining the 24 year old's team who they are able to lead now since they have an extra 3 years worth of experience + context in the specific area.