As a WSH, (white Saxon Hindu) I am very confused about Jati and Gotra. The more I read, the more confused I get. It seems to me that Jati and Gotra are hereditary social constructs based on the varna system which does not seem to be originally hereditary.

If I am wrong, please correct me. This has become problematic for me, in that so many people say that only those who are born Brahmins are qualified to act as pujaris. They say it's in the DNA, but I see so many Brahmins who abuse their position, and who choose not to practice the Brahmin way of life.
There are others, who are not Brahmins by birth who claim to have the knowledge and wisdom and who claim to live the life, who would like to officiate at pujas, but are blocked from doing so.

So, for example, if my father was a household servant, can I still become a school teacher?