I could probably float a lot better today (ha ha), but do not have the desire to swim anymore.
You could likely float then, but your body reached equilibrium several feet under the surface and it just felt like you were going to sink like a rock. Low body fat and high bone density do make it more difficult. Obese women float on the surface particularly easily. Muscular, athletic people not so much.
Have had bone density tests. I have really dense bones. I never could float So white I reflect.