Why did she sleep for 5 years?

I was also wondering why she slept for 5 years, and didn’t even consider the plant. I just thought it was cause her body was changing ヾ(❀╹◡╹)ﾉ~

Maybe bcs she matured as a dragon?

Maybe...
This might be wrong but my theory is that the reason why she fell asleep for 5 years may not because of the tears but bcause of her growing phrase(?)
Remember the time when she returned back to the Etam family and Ayrin fell asleep while her father carried her? She fell asleep for at least 2 weeks, right? My guess is that, this was the time when she first grew her small wings and it finally showed her wings when she collapse after saving her father. Then , the latest one is about the plant. After her tears fell on the seed, the next day she said that her head was hurting the moment she woke up skip scene~ she collapse at the palace and returned back to her ori world
My guess would be like that dragonia plant growth causes a clash which triggered her back to her original world while Ayrin's body was in growth phrase changing her from lizard form to a complete dragon form during the sleep..

This also could mean a few minutes in her Original world is a long ass year in Ayrin's world XD but oh well
( Wow I don't even know if this makes sense but Yes it may be wrong XD )