I’m probably the last person who should be giving wardrobe advice but this is important:

Never trust the dressing room mirrors when trying on v-necked tops.  They will lie to you.  If you really want to know how your new v-necked top fits wear it to work.  On a day when you have lots of meetings.  Sometime around noon you will realize that the top is cut way too low and needed to be worn with a camisole underneath.  I’ve tried this at least five times now.  It works.