Wow, sorry to hear about your girlfriend. Commendable though, that you are moving on.
Your drawing looks great, nice linework! If you want to put some flowers in there, maybe you could have them bordering the image. Maybe something art deco or nouveau inspired?
To be honest, and it's only my opinion, I don't like the "rest in peace" for lettering. Maybe her name if you put in lettering and I think it could be nice without lettering too.
You are a level 8 ninja and even though you have a lot of weapons sometimes your ninja moves are your most powerful.