she was starting to get through to Anakin and probably would have been able to snap him out of it and turn him back if not for Obiwan suddenly showing up from inside her ship which drove him further into his hate
Impossible to say for sure... Anakin was so messed up already at that point. He actually lobbed off Mace Windu's arms despite knowing full well that Palpatine was the Sith Lord they had been searching for years. That same Sith Lord that threatened Padme's life on more than one occasion.
No, Anakin couldnt go back to the Light by that point, not after slaughtering all the Jedi and the kids. He'd really chosen Palpatine over Padme, even if he was fool enough to think he was acting in her interests.
No, he was Palpy's minion by that point, and he'd tried to change sides again the old SOB would have killed him or broken his mind. Anakin had serious power but he was still young and really stupid, he wouldn't have had a chance against his With master.
“Seventy-seven courses and a regicide, never a wedding like it!
he came back to the light decades later after killing billions more.
when Padme was talking to him you could see in his facial expressions that he was starting to listen to her.
and then Obiwan showed up and ruined everything (Anakin already had resentful feelings for Obiwan since the second movie) so it tipped the balance back to the dark side.
Padme was the only one who could bring him back at that point (and later only her children).
I think that's why Palpatine killed her from afar and then smiled after Vader learned about it. that's when he knew that Vader will never turn back to the good side.
He came back to the light when he was old, strong, and well-experienced in Sithitude. Even then, fighting Palpatine cost him his life, he only succeeded because he was willing to sacrifice his own life to win, Palpatine was still stronger.
If he'd tried to change sides again as a young man, there wouldn't have been anything left of him but a little grease spot.
“Seventy-seven courses and a regicide, never a wedding like it!