I started at 16.
Unfortunately, I had a huge setback, but I had some good fortune, too...
I started working at age 13. When I turned 16 I had enough money to buy a car (I actually bought 3... lol). I owned mutual funds at 16 and kept contributing. Then when I turned 18 I started buying stocks and trading. I continued doing that until 22 when I bought my first house.
After buying my house, I struggled a bit. I rented out some of the rooms immediately, but carrying the mortgage and being a homeowner and landlord was both new and difficult at the time. Tenants damaged some things. I had to get a new roof after like 2 years. And then when I was 25, I got fired from my job. It was stressful. I really didn't make much money to begin with to be able to pay for the house and save. I was only making 43k/year at the time and my stock trades were my only real source of adding to my retirement.
After being fired (for which I was fired without cause and received a small settlement, at first they offered 13k and I pushed back on them and they offered 15k. I accepted the 15k and moved on with my life). I basically applied to jobs non-stop for a week and didn't sleep.
Luckily for me, I got a job 6 days after I was fired. Unfortunately, the new job was not great. It was a job for high schoolers and required no education. It didn't have any benefits of any kind (no medical, dental, RRSPs, or anything). The hours were not guaranteed and it was a flat rate of $20/hour selling bullshyt products door to door. But I did it. Then I fell into the wrong crowd. I was drinking a lot. Even drinking at work sometimes with the other employees. One night, we all got caught and we were all fired. I only worked there for less than a year.
Now, being almost 26 years old, I had no job again. So I started my own business as a wealth manager because cars, fish tanks, and finance is all I know or am good at. I day traded and wrote options to pay my bills and I managed money for some clients on the side. This whole time, still dealing with a revolving door of tenants in my own home which really sucked and was very, very stressful.
After 3 years of living off the market and managing money for my clients, I f(_)cked up one of my trades. I over leveraged myself on margin and borrowed a few hundred thousand $USD. I put it all into CVS @ $69/share by selling naked put options. The price of CVS sank. Then it sank some more. Then some more. And soon it wasn't just the stock price that was sinking, but so was my heart and my confidence. I finally pulled the plug on CVS. I had lost just shy of $80,000 $CAD. The balance remaining in my brokerage account was only $16k and I once again had no money, a mortgage to pay for, a car loan of $20,000, and no real job except for my own business.
But I didn't even have my own business after that. I had lost confidence and I could no longer feel good about managing other people's money, so I sent an email to my clients telling them I was done and I fired myself.
Back to the drawing board I went, swallowing my pride, I stayed up day and night applying for jobs and delivering food for every gigwork app I could. I would sit in parking lots and apply to jobs on my phone waiting for delivery orders. I got a job after a couple months and I was about 28 years old or so at the time. This is my current employer and I am now 34 years old. I started at the bottom, making 40k a year (for the 3rd time). I hustled hard, took all the overtime, cut my expenses. I would deliver food for the gig apps every day after work and all day and night on weekends. I never took a day off. I paid off bits and pieces of my car loan until it was gone and then I started rebuilding my stock and trading accounts.
In the span of those 6 years between 28 and 34, I went from a single house with a $20k car loan and $16k in a brokerage account at a 40k salary... to now having 2 properties and $350k+ in liquid assets.
So, yes, I did start saving for retirement at 16, but I messed up along the way. I learned lots of things. Some good things, some bad things. I had some fun, and also some very tough times.
I didn't mean for this to turn into a story but I guess it kind of just ended up that way. In any event, I guess it's never too late to start.
People always say you should buy the dips in the market, but maybe what's more important is to double down and buy the dips in your life.