Neither, we usually say, wow, (s)he's grown up so quickly. Hope this helps.

Only the first one is correct, but is past tense. The second one is just simply incorrect. To make a present tense expression, you would probably say, "Wow! She is growing up so fast!" Both of these expressions would be used. For example, I knew my niece very well when she was a baby. We were away from each other for 20 years. It seemed like a short time, but when I saw her again, she was an adult. My expression was, "Wow! That doesn't seem possible! She grew up so fast!" If I see my other niece who is now 9 years old, she is not yet an adult. In this case, I would use an expression like "Wow! She is growing up so fast!"

"Wow! She has grown up so fast!" You're connecting the past to the present, so only present perfect can be used.

Great information, Thank You. All you who have issues with the lover but want relationship fix . here is the info of Dr Obodo a top spiritual healer ____ _____ templeofanswer( @) hotmail . co . uk _____

[email protected] Hello , My name is Voice Philip , I saw your profile today at this site (http://www.italki.com) I became interested in you , i will also like to know more about you, I want you to write me directly to the email address my own , and I have reason to connect also secretly to say you, and I promise to give you more details about me and give you my pictures for you to know whom i am . Here is my address ([email protected]) Write me directly to my e-mail and I think we can move from here! And remember that the distance or color does not matter anything but love matters allocation in life. I am waiting for your mail to my email address above private See your reply soon voice.