Do I have a case in probate court if I haven't seen my father/grandparents in 22 years?

[James]

I have not seen or talked to my biological father (he is on my birth certificate) or my father's parents since I was about 8 years old. The story behind that is too long for the purpose of this question. I am 32 years old now. I have been informed that my father and grandparents passed away about 2 years ago and had property close to $3,000,000 in worth. My sister (45 years old) informed me of their death and that my uncles took most/all of the assets. Where should I go to investigate whether I was excluded from my father or grandparents will/trust if they had one? If I was not specifically named (excluded) don't I have a just claim to some share of the inheritance to my father's estate and my grandparent's estate if they set up a trust to be divided among their descendants in equal shares per stirpes? My father and grandparents lived in California and their estate would have been in California. Do i need an attorney now or can I get copies of the trust/will myself even if I am not named as a benificiary. Do I have a reasonable case in probate court if I am not mentioned that they forgot about me?