That will be for first time
You can make a hard reset
If it still occurs, then dont worry, sometime it happens due to confliction of other apps which are running on the background
And after you run the app for first time, then second time it wont took long time
Even we have computer with Core i7 processor but still we see some apps took upto 1 minute, depending on the size of app
Facebook is a large size app, it took time because of its size
Sometimes other apps took place in RAM in the background and keep running
This let the new closed app to run slower
Once it runs and took its own place on the RAM then it run smoothly next time