[Five years is nowhere near enough. I mean, uh...]

It's up to you, whichever you would prefer. I certainly don't mind going by "Litchi," though. [She really isn't one to ask about formality, because she can happily tote honorary titles for years upon years. But hey, she doesn't mind informality around her.]

I'll be sure to keep your offer in mind just in case. Thank you very much.