"I think I've outgrown this one too, babe"
Slowly, over the past few weeks your girlfriend had been steadily getting bigger. Just in the first week her budding A-Cups swelled up to a sizeable D-Cup. Three days after that she was a large H, and had grown from her short 5"1' to a elevated 5"3'.
The doctors said that she seemed to be having an aggressive "second puberty", causing her to recieve an increased amount of growth hormones, causing her to get bigger. By the end of the month, she was sitting at a towering 6"9', with breasts larger than her head and as ass almost wider than her shoulders with her growth not slowing a single bit.
"I think I'm growing faster, this top didn't even last me a day!" Said your girlfriend, saying from her new 7"1' vantage point