Lara Spencer had a heartfelt message for her daughter, Katherine, on Monday as she celebrated her offspring's birthday and her social media followers were blown away by the photos she shared on Instagram.The Good Morning America host was feeling a little nostalgic as she posted snapshots from when Katherine was younger and then as a very tall teen today.MORE: Lara Spencer shares then-and-now photos for heartfelt reason She wrote: "And just like that-she’s 17. Happy Birthday beautiful girl.