What matters is what you've accomplished during the time you've been studying your instrument, regardless of how long it took you. And even that doesn't matter unless it matters to you.
In any case, I hope you've been doing other things during that time, like holding down a job, raising children, eating, and what-have-you. Hey, why not keep track of how many hours you've been actually playing? That would be some useful information. Or would it?
I don't generally care for "resume currency": the type of information that would appear in a third-person bio. And as a rule, I dislike third-person bios unless you are so important that there's a Wikipedia entry about you.
Maybe it's because I went to state universities and public grade schools, or because, as one of four children, I didn't have the kind of upbringing that allowed me to begin violin lessons at age three, or because I don't have an advanced degree; whatever the reason, I consider details about someone's age, education, and the rest of their curriculum vitae to be not very important. While at times this attitude has been naive, it has also at times allowed me to escape the status quo and find my own way in the world.
So, the number of years (or hours) you've been playing is just a number. But people want this number because it helps them figure out where you are, and where they fit in. People use your number to rationalize their own choices.
When both of my maternal grandparents passed away from lung cancer in the same month (having been divorced for forty years, by the way), people asked me, "Were they smokers?" The real question was, "Could this happen to me?"
Below, some of the questions musicians get asked in this vein.
Question: "How long have you been playing?"
Subtext: "How long will it take me/my kid to get as good as you are?" or "How long have you been playing compared to me, and how do I rate against you?"
Question: "How old were you when you started playing?"
Subtext: Same as above.
Question: "Did you come from a musical family?"
Subtext: "If the answer is yes, then that explains your talent, and explains why I could never have been a musician."
Question: "How old are you?"
Subtext: "How do you compare to me when I was your age?" or "Where do I want to be when I'm your age?"
Question: "How long did it take you to learn that?"
Subtext: "Should I even bother?"
I have worked with a great many students in my career (How many? For how long? Meh.). I've learned that their struggles, slumps and triumphs cannot be measured in years.
It would be helpful if there were some external metric we could use to assess whether we are succeeding, whether we are in the right profession, whether we're playing the right instrument, whether we should even keep going. Since there isn't, I recommend the following:
"If it sounds good, it is good."
"If it feels good, it is good."
And, “The art of music is divine and effective. It is the food of the soul and spirit. Through the power and charm of music the spirit of man is uplifted." - 'Abdu'l-Baha
And of course, "Hail, hail, rock'n'roll!" - Chuck Berry
I don't care how many years you've been playing. Just keep playing.