Not everyone can be a good singer but it has little to do with age
Even the best singers start to lose their voices when they reach their 70s and 80s. At 28 you are nowhere near that. It is not too late to try.
However people are born with their anatomy and the anatomy of head, throat and chest make a voice beautiful or not. Just as people are born to be a successful athlete or not, or to be a model or not.
I know this from my own personal experience. I have taught classical guitar and I have been in all sorts of bands. However despite trying all avenues, I am not a singer.
Am I trying to discourage you? No, but for those who have the natural ability, it is all too easy to raise false expectations in those who don't.
My message is to stop being embarrassed.
If you want to see someone who can't sing at all and has zero embarrassment about it, listen to anything by William Shatner of Star-Trek fame. Here's an example
Go to a teacher that claims anyone can sing. They will, by the very nature of their job, have dealt with all the worst voices imaginable. You won't be anywhere near the worst. They won't be embarrassed and neither should you. Either they will succeed and you will be able to sing or they will fail thus proving themselves wrong - you can ask for a refund!
There are even choirs that are especially for people that can't sing but don't care!
That’s what makes The Tuneless Choir such a curious little society.
They don’t cringe at tone-deaf vocalists; they actually welcome clumsy
singers with open arms. If you can’t ever seem to hit the right note,
you’re a perfect fit for membership.
https://themanc.com/news/choir-for-bad-singers/
Here's a story that resonates with my experience -
The reasons for being a poor singer are
(1) inability to hear notes correctly (being tone-deaf) - there is no cure for this and to tell a tone-deaf person otherwise is inconsiderate - I have a friend who really is tone deaf and she hates people telling her how easy it would be if she only tried harder.
(2) inability to reproduce notes that you've heard - this can be improved with practice and exercises. It involves improving agility and accuracy of the vocal tract
(3) inability to keep a steady rhythm - this can be improved with practice
(4) the lack of resonance, in your head and chest. This is purely an anatomical phenomenon (it also happens to be my problem). People with truly beautiful voices are born that way and the opposite is also true.
Alternatives
There are get-outs. If you can't sing then maybe you can rap. There is also a technique of musical "talking". In classical terms it is called Sprechgesang.
https://en.wikipedia.org/wiki/Sprechgesang
It has been quite popular with famous actors who have good speaking voices but can't hold a tune. I've already mentioned William Shatner but there are many. Anything that involves Rex Harrison 'speak-singing' is worth a listen.
I'll tell you my experiences if you're interested. I ended up being a good musician but never a singer. (pass mouse over the box below)
At my first school I was asked by the teacher not to sing when the class was singing. She said my voice was "too gruff"
I was rejected for the choir at my next school. I was also told to mime but not sing in assembly
When I first heard my recorded voice I understood why. I was reasonably in tune but the tone of my voice was terrible.
On various occasions I have been asked not to sing. For example as a student, I had a boring holiday job - I would sing while I worked. One of the workers actually came up to me to say he had drawn the short straw to ask me to stop as no-one could stand it!
Later I decided to have singing lessons. I did the exercises religiously. After 8 weeks the singing-teacher told me she couldn't do anything with me and was discontinuing the lessons.
While all this was going on I took up guitar. I ended up playing in bands and had many years of musical enjoyment. I also qualified at a London music college and was a successful classical guitar teacher.