Enjoy every moment, it's a wonderful time and passes all too quickly. Make a note of the funny things she says or you'll forget them. I have a diary full of my grandsons' quotable quotes. At 8 and 6 they're still coming.
Daughter had to explain what a pinnace is/was to her class. (It's a type of boat) 8 year old "Mummy, why are you teaching the children about penises?" Fortunately the Y10s were not so quick!
Yes you must write them down. I can remember some of my daughters’ early words but have forgotten so many. Faffout - cornflakes (??), Bampout - elephant, Arker Kit Kiss - Father Christmas. Language is wonderful.
One of our grandsons had realised that to form the past tense of a verb you usually added ed; hence he decided the past tense of do was dooded. We still use it.
I too love it when little ones say 'actually', my grandson floored me once when in a serious voice and with folded arms he said 'In particular, which ones?' when I asked him to put his toys away.