Can you characterize your own genotype? If so, how, if not, why?

This can only be done partially.

First, you can analyze the appearance and establish which of the signs are dominant and which are recessive. For example, dark hair and eyes, dimples on the cheeks and chin are dominant features, blonde hair and eyes, lack of dimples are recessive.

Secondly, in order to establish heterozygosity for any of the signs, it is necessary to analyze the appearance of the parents. For example, if mom is blue-eyed and dad is brown-eyed, then you are brown-eyed and heterozygous for this trait.

Thirdly, many genes do not manifest themselves externally (for example, some diseases), so it is impossible to establish the genotype without analysis.