Assuming you are referring to Harry's fourth year, Barty Crouch Jr disgused as Alastor 'Mad-Eye' Moody was helping Voldemort.
About one year.
Lord Voldemort was 68 when he returned in June 1995. He would turn 69 in the December of that year.
Yes, that is Lord Voldemort's real name. Tom is a memory of his sixteen year old self.
In Harry Potter and the Chamber of Secrets we learn that Lord Voldemort's real name is Tom Marvolo Riddle.I am Lord Voldemort is an anagram of Tom Marvolo Riddle.
On the back of Quirrel's head.
No. Voldemort gained his first followers at Hogwarts. Although it is unknown what year Professor Quirrell was born in, he certainly wasn't old enough to be have been at school with Voldemort. Quirrell met and joined Voldemort in 1990 during a year long sabbatical.
Lord Voldemort was never shown to directly kill a first year, but during the battle of Hogwarts some first years may have been injured or killed if they'd sneaked back into the castle.
Lord Voldemort. When Harry was a one year old, Lord Voldemort came to his house with a plan to kill him. Lord Voldemort accomplished killing Lilly and James, Harry's parents. But not Harry. When Voldemort tried to kill him with the killing curse, It did nothing but put that scar on his head, and a part of Voldemort's soul was now in that scar. That is why Voldemort was so weak, Because he gave his soul away without meaning too. And that made him a horcrux. A horcrux has parts of Voldemort's soul into it. And the only way Harry could kill him, is if he died as well.
Lord Voldemort does not have a job, he is a full time dark lord. He was a former assistant at Borgin and Burkes and he applied for the position of Defence Against the Dark Arts teacher but was refused - he then cursed the post so nobody could hold it for more than one year.
On the 31st of October 1981 when he was attacked by Lord Voldemort when he was a one year old baby.
Lord Voldemort placed on a curse on the position after he failed to get it.
Other than Potions, it is unknown which subjects Voldemort studied. We know he took Potions at N.E.W.T level because he was in Professor Slughorn's sixth year class. Voldemort was a very good student, so it's likely he could take any subject he wanted.