I congratulate you for working up to ask for help in this. I do a lot of genealogical research on my family, so I know how exciting it is to find something that is surprising – in this case, perhaps life changing.
My first suggestion is that you contact your local orthodox rabbi or local orthodox beit din (rabbinical court). There are Rabbis who can help guide you through the process.
My second suggestion is to write down everything you can remember about your family’s heritage, and collect whatever documentary evidence you have. Speak to older relatives if you have any of advanced age from your mother’s side to develop more information.
You may want to also research online to find community records, relatives, etc. I would suggest (mods, please allow) jewishgen.org as somewhere to begin that side of the research.
My third suggestion is that you consider very carefully what identifying yourself as a Jew will mean to you. As you must know if you have been reading here for a year, there are a multiplicity of opinions and perspectives in the orthodox world. But there is one thing all agree upon, and that is that where there is a question of Jewishness and a conversion pro forma (known as giyur lechumra) is required, as with any conversion, a sincere, wholehearted, and devoted lifelong commitment to the observance of mitzvos in an orthodox manner is a requirement, the abandonment of which will invalidate the conversion.
Finally, you seem to be able to find Jewish resources on the internet, so I won’t belabor you with suggestions. There are many sites to learn from, but nothing online will compare with building a relationship with an orthodox Jewish family or community where you live.
I wish you much hatzlacha (success) in your journey.