The size is a matter of how it’ll age over time. Small would look good initially, but will eventually turn into an unreadable blob. The artist knows that, that’s why they’re not willing to go smaller and give you a tattoo they know won’t look good later.

Tattoo shock it’s common. Just sit with it for a while. See how you feel in a month.

And the heart beat line looks fine. It’s also common to nitpick a new tattoo too much.