To read about the story of Aisha's Marriage, let's look at the Tabari's source.
The History of al-Tabari volume 9 page:130-131
"My mother came to me while I was being swung on a swing between two branches and got me down."
Here Aisha's mother is the one who got her down from the swing. How little will be she if her Mother is needed to got her down.
Messenger of God was sitting on a bed in our house. [My mother] MADE ME SIT on his lap
The mother of Aisha put her in the lap of Muhammad who was sitting on her bed. Now let's check if whether Aisha know what is happening there. We can see that from Aisha's Mother's words:
and said, "These are your relatives. May God bless you with them and bless them with you!"
There is even no proper introduction to her what will happen to her on that day.
The Messenger of God consummated his marriage with me in my house when I was nine years old.
Did you note that Allah's apostle didn't even conducted a wedding feast for Aisha's wedding. But we can se grand wedding feast to about 300 people (Sahih Muslim 1428g) in Zaynab's wedding. Sahih Muslim 1428c
Anyway, leave that aside. And focus on Aisha's marriage about her age and Muhammad's interest on this child. So we did see, she was 9 year old when Allah's apostle consummated the marriage.
Now let's see how this marriage happened and whose interest this was.
Read it from History of Tabari - Volume 9 (page:129-130)
Muhammad is the one who initiates wedding, he is the one who proposes marriage to Abu Bakr. And if you read the situation, you could see that even Abu Bakr first told that Aisha is like Muhammad's brother's daughter. And we can see that Muhammad AGREED TO IT and says that still Aisha is halal for him.
This is also mentioned in Sahih al-Bukhari 5081
Now read Sahih al-Bukhari 3894 to know the reason why Muhammad consumated marriage some years after; it was because of the fear of the ill of Aisha and not because of her puberty or something.
Aisha was a small child who plays with her dolls with girlfriends when Muhammad consummated his marriage according to Sahih al-Bukhari 6130
One may say that this playing was before he consummated the marriage. But there are lots of other Sahih hadith that are against that claim. Check these interesting hadiths Sunan Abi Dawud 4932
Note that this incident happened after expedition of Tabuk or Khyabar; during the battle of Khaybar, Aisha was 14 years old. This can be read from Fath Al-Bari vol-10 page 544 or from إسلام ويب - فتح الباري شرح صحيح البخاري - كتاب الأدب - باب الانبساط إلى الناس- الجزء رقم10 (islamweb.net)
At that time Aisha was a little girl who has not reached the age of puberty.
Now look at this hadith Sunan an-Nasa'i 3378
We can see that Muhammad only saw second time when he consummated his marriage after his marriage contract with her when she was 6 year old. Check History of Tabari - Volume 9 (page:131)
So we can know that Muhammad consummated his marriage with small girl who play with dolls. Isn't that morally wrong for a Prophet to do? And we cannot see that he repent for this sinful act he has done.
One more hadith which says about that Aisha was not reached puberty. Sahih al-Bukhari 5236
When we dig a little deep in Quran At-Talaq 65:4 we can see that there is Talaq (divorse) for those who have not menstruated. You can get to know more about it in Nikah with not Menstruated
Don't get confused that some Muhammadeeyans may say consummated doesn't mean to have sex, for them show this hadith Sunan Abi Dawud 2121
Did you read the Chapter heading: Regarding The Marriage Of The Young
Look at the time line of Aisha
One may ask why Muhammad doesn't have intercourse with Aisha when he married her. The answer can be found in Ibn Sa'd: The women at Madina Volume 8 page 45 translated by Aisha Bewley
We can find that Aiha was 18 years old when her husband Muhammad died, we can find the reference of it in History of Tabari - Volume 9 (page:131)
So even at her age of eighteen when Muhammad died, Aisha says she was at her EXTREME YOUTH.