How many kills is too many as a support Bard?
So, I'm learning Bard. Wound up going 11/2/18 in my most recent game, without intentionally KSing. I was playing with friends, so it wasn't a major issue, but there was some grumbling that a support should never get so many kills. I get that, but hey, I'm a bursty support, and if my ult is down I don't really have any role in a team fight beyond trying to out-damage the enemies with my empowered auto-attacks (and peeling with my Q, but that's just more damage).
I realize that there's obviously no hard rule of thumb, but what are your thoughts on a burst support like Bard getting fed? I sure as hell don't want to let a critically wounded ADC escape a team fight or get a peel and do more damage, right?

(Depending on the build he can one shot people but rare to find people doing it...)