I'm not Jewish but I'm going to Erev Yom Kippur, what can I expect?

Just go accompanied with a friend -- you will feel better. Stand up when the congregation stands up and sit down...when people around you sit. Most important do not chat...just listen and read when necessitated. You will be ok. It is a great day. End of the services repeat the same words people tell you -- shana tov. or Yom tov.

Yom Kippur is a Day of Atonement for all who understand man is in a fallen state since the expulsion from Eden. Torah says that YHWH told people in the desert to make atonement for their sins (errors). This will be remembered in this Shabatt. What it is not understood yet in Judaism, is WHEN is the Messiah supposed to have accomplished what is prophesied in Isaiah 52:13-53:12 which I include here for your reading. Jews in the first Century thought this was accomplished by Yeshua (Jesus) and continued to be Jews now understanding Yeshua's New Covenant with Israel. He was the Atonement and the sacrificial Lamb. Please listen to the ceremony carefully, do not try to convert any one (if you do not consider yourself a Jew), be very respectful and hope for their kindness. Torah said anyone coming to Israel embracing God of Israel, should be treated as an Israelite. You have to understand, when a Jew sees a "Christian" all he sees is an Inquisitor, sadly, but that is reality. 13 See, my servant will act wisely; he will be raised and lifted up and highly exalted. 14 Just as there were many who were appalled at him- his appearance was so disfigured beyond that of any man and his form marred beyond human likeness- 15 so will he sprinkle many nations, and kings will shut their mouths because of him. For what they were not told, they will see, and what they have not heard, they will understand. Isaiah 53 1 Who has believed our message and to whom has the arm of the LORD been revealed? 2 He grew up before him like a tender shoot, and like a root out of dry ground. He had no beauty or majesty to attract us to him, nothing in his appearance that we should desire him. 3 He was despised and rejected by men, a man of sorrows, and familiar with suffering. Like one from whom men hide their faces he was despised, and we esteemed him not. 4 Surely he took up our infirmities and carried our sorrows, yet we considered him stricken by God, smitten by him, and afflicted. 5 But he was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was upon him, and by his wounds we are healed. 6 We all, like sheep, have gone astray, each of us has turned to his own way; and the LORD has laid on him the iniquity of us all. 7 He was oppressed and afflicted, yet he did not open his mouth; he was led like a lamb to the slaughter, and as a sheep before her shearers is silent, so he did not open his mouth. 8 By oppression and judgement he was taken away. And who can speak of his descendants? For he was cut off from the land of the living; for the transgression of my people he was stricken. 9 He was assigned a grave with the wicked, and with the rich in his death, though he had done no violence, nor was any deceit in his mouth. 10 Yet it was the LORD's will to crush him and cause him to suffer, and though the LORD makes his life a guilt offering, he will see his offspring and prolong his days, and the will of the LORD will prosper in his hand. 11 After the suffering of his soul, he will see the light of life and be satisfied; by his knowledge my righteous servant will justify many, and he will bear their iniquities. 12 Therefore I will give him a portion among the great, and he will divide the spoils with the strong, because he poured out his life unto death, and was numbered with the transgressors. For he bore the sin of many, and made intercession for the transgressors.

Yes they will ask. You will likely have to stand or sit way in the back as all the good seats are sold and their books are in Hebrew so you won't know what when or where the service is. Whether you will be allowed to stay really depends on the type of synagogue you visit.

wear a kippa or something on your head atleast...r u also fasting? i think dont lie, just say no and then tell them your interest in being there