I have been seriously thinking about changing my name to
Violetta and I also would encourage you to use it. I don't find it to be too much of a name at all. I would personally not use a nickname but that's just my preference. I don't know why many many people on btn seem so set on needing a nickname for everything but
Violetta is only four sylables (sorry for bad spelling). If you really wanted a nickname I would suggest Letta. To me
Vita is so "old school" if you know what I mean. Best of luck !