On the last day of August, in 1991, Harry thought he'd better speak to his aunt and uncle about getting to King's Cross Station the next day, so he went down to the living room.

"Uncle Vernon?"

Vernon grunted to show he was all ears.

"I need to be at Kings Cross tomorrow to go to Hogwarts. I've to take the train from Platform 9 and 3/4 at eleven o' clock."

The next day, Harry and the Dursleys arrived at half past ten at Kings Cross station, where Uncle Vernon dumped Harry's trunk on a trolley and wheeled it into the station for him.

Eleven year old Dudley suddenly speaks for the first time since they reached London. "Mum! I heard you and Dad last evening talking about some platform where you'll see the train leaving for Harrrys school! You've to enter a magical something, right? I want to see it!! You've been there, haven't you?"

"Dudders!" Aunt Petunia was white in the face. Uncle Vernon looked simply annoyed. "You shouldn't eavesdrop on others conversations!"

"All the more. I still want to see the place!!" Dudley began throwing a tantrum.

Petunia glanced at Vernon in apprehension and seemed to make up her mind while Vernon looked like this might as well be some stupid prank.

For the first time in Harry's memory, Aunt Petunia held Harry tenderly on his shoulder with one hand and started pushing his trolley with the other hand.

Harry saw ahead and was horrified to see they were walking, no, jogging straight into the opposite wall! He closed his eyes and braced himself for the crash but nothing happened. When Harry opened his eyes, there was a board saying "Platform 9 and 3/4" and a train called "Hogwarts Express" stood in front of him!

"I came here with Lily, Mum and Dad several years ago to send Lily off to her first year at your school." Came Aunt Petunia's voice as she went back through the barrier again, reappearing with her husband and son this time. Vernon and Dudley looked simply awestruck seeing the platform and the train! However, they were still wary of the wizards standing on the platform.

Besides, Dudley's tail had begun to attract the attention of those passing by. Petunia told Harry to take his trolley further into the platform and climb the train.

As Harry went forward, he looked back in time to see Aunt Petunia, eyes full of jealousy for herself not being magical like her sister and nephew, disappearing through the barrier back into the Muggle World.

Harry walked on when he saw a red haired family. There was a mother, her four Hogwarts ages sons, and her youngest daughter. The mother was advising something to the boys, while she kept telling the girl she was too young to go yet.

Explanation-

Petunia and Lily were sisters, but Lily was magical (and could thus attend Hogwarts) while Petunia was non magical so she couldn't attend Hogwarts although she wished she could. As resentment and jealousy filled her up, she began loathing Lily and anyone Lily was with and this continued even after Lily's death. Petunia never gave Harry the love, affection or care that he needed, but spoilt her own son, Dudley in contrast, just to take revenge.

It is revealed later in the series, along with the above information, that Petunia had even written a letter asking to be admitted but was denied admission into Hogwarts so she grudgingly watched her sister board the Hogwarts Express. However, despite knowing this, she pretends in front of her husband as well as her son that magic is for freaks, that Harry is a freak like his mother and father. Petunia doesn't even show Harry where to catch the train on his first year despite knowing where the train must be caught or where the platform is.

Therefore, in my fan fiction, Petunia takes Harry, her husband and her son straight to Platform 9 and 3/4 that one time, instead of in canon where Harry had to rely on others (and met the Weasley family) to get there.

Hope you liked this.