Junior Developer isn't an insult, it's just someone who may need about 1/3 of your time to showing them around.
A "Developer" without Junior or Senior should require 1 day out of 14 for advice/assistance.
A Senior Developer should only require assistance when the building is on fire.
A principle engineer invents new kinds of fire.
Kindle. Fire. I'll see myself out.
(Douglas Adams, https://books.google.co.uk/books?id=YKHJ6WQKD3YC&pg=PT142&lp... )
In my mind the difference between a junior developer and a senior developer is the ability to recognize tasks/issues and accurately prioritize them in alignment with organizational objectives. In particular I've found that when left to their own devices junior engineers tend to focus on irrelevant items and metrics such as lines of code or genericness for genericness' sake where senior engineers target important bugfixes and features that bring highest benefit to the company and customers. There are parallels with this statement and the premise of the parent comment but I think the latter draws with too broad of a brush.
Intellectual strength isn't the same as senior developer. There might be correlation but it's probably not super strong. I agree that someone not asking for help is definitely junior. But I might also argue that someone who does need to ask for help probably isn't as senior as you seem to think they are.
Even the worst developer can eventually develop fluency in a poorly-designed codebase and seem much more competent than they actually are, compared to a new hire.
But a senior will definitely ask when he needs help, and won't wait until someone comes to him. And even without the right help, he'll still figure out some way to move forward. Usually, he can figure out his own problems while also offering assistance or guidance to others.
I mgiht guess that a senior developer asks for assistance when it will save them time - they could work it out, but it'll be more efficient for everyone involved if they get some assistance - whereas a junior developer would be lost without it.
But ultimately, anyone can get stuck hunting for a typo causing an inexplicable problem. Sometimes you just need someone to explain your problem to, just to help your own head to solve it.
That said, it's totally possible you were there, yes. The pacing of promotions vs the abilities needed for them are not always correlated appropriately.
Age is not a good predictor.
When someone is at the level of SE, they have proven they have skills beyond slinging well-formed code - that's entry stakes for second-tier. They demonstrate a wider understanding of how their work fits into the overall product development, an understanding of customer perspective, and many other attributes. Most if not all of these derive from knowing the right questions to ask, the right people to ask them of, and the right time to do so.
The biggest differentiator is that the Senior developer should know when she needs to ask questions to proceed.
Senior developers require assistance all the time. Once problems are complex enough there isn't much that can be done as a solo ninja.