I am 55 years old,i still have a good shape,and my skin as silk?

i am 55years old,and maybe you don’t believe me,i still have a good shape ,and my skin as smooth as silk.i just look like a
25years old. i am proud of these
and i feel very confident.you can see below


but yesterday i wore this sexy swimwear to go to the beach,i found they laugh at me,oh.it made me lost my confidence,but
i don’t know what was wrong?can you tell me the truth and give me some suggestion?