When I opened my first account on a dating app after a long-term relationship ended, I was in my 40's. I shaved a couple of years off my age with the rationale that everyone lies on their profiles.
After a year of meeting several different people I found the majority were truthful in their profiles and were truthful in their messages to me. Don't get me wrong. Dating has liars, manipulators and catfishers but most of the people I met were honest and were dating the best they knew how.
Eventually I changed my profile to reflect my true age because I didn't like to admit that I had been dishonest on my profile. I would stress about whether I should tell the other person I lied about my age up-front or after a few dates or just not say anything at all.
Most of the time I said nothing but it is a shitty feeling to drag around with you, so I encourage you to always be honest. You don't have to shout all your faults from the rooftops, but building a foundation of trust is crucially important. So don't fuck it up with a lie. You'll never regret telling the truth. I was born in 1976!