Yes, that. It's possible she might do the same theme twice in a row but it won't take many trips to get through however many remaining fashion checks you have left.
I have posted this before so I can just copy & paste it when someone needs it.
GRACIE GRACE HOW TO
It is VERY random when GracieGrace shows up but when Gracie does show up or you remember the date he/she was there before...
Go to the plaza/town tree and Gracie should be there.
Gracie is there ALL day long, beginning at 6 am until Midnight.
Get your theme.
Change your outfit.
Go back to Gracie and pass.
Save & Quit.
You might want to do a quick daily routine (to make sure no one is moving) before you change the time to re-load the day.
Change the time to 5:59 am the day she showed up, with Isabelle or the 3ds system clock.
Come out of your house and let it go to 6 am and you will come out of your house again.
Rinse and repeat.
Just do this over and over again until you pass all 4 Fashion Checks.
If she gives you a hard theme (modern), have a 2nd character go to her and get a different theme and pass it as them.
You only need to have spent at least 70k in TIY for Gracie to show up. Spend another 30k (100k total), pass Gracie's fashion check 4 times and at least a month has passed since you got TIY for the final store upgrade to happen. But if you do a little bit of TT (because of the Gracie's fashion checks) then it can be a little less than a month because each day you go back and forward counts towards the total of 30/31 days.
If you do this you can pass all of GracieGrace's fashion checks in the same day, but your turnips will SPOIL.