My sister wants me to pick a different baby name

I'm currently 12 weeks pregnant with my first and we did a Sneak Peek test at their clinic that came back a boy! We are so excited! We've had our boy name picked out since my last pregnancy that ended in a miscarriage. We want to name him Jonathan Randall after my dad Jon and my hubby's dads middle name Randall. Well my sister and best friend has a 3 year old named Jack and she says I should think of new names because Jack is another name for Jonathan. I kind of remember my mom talking about Jack being named after my dad but I don't think the two names are that much alike. Do you think I should stick with the name or should I change it to something else?