Am i being crazy or over thinking ? Help

Okay! So my husband and I like two names we love love love Oliver and we really like Carsen . However my step moms sister has a one year old named Oliver, I havent seen her in like 7 years never met her kids however this is my Dads only grandson I'm not having anymore kids and am an only child i had my heart set on Oliver untill i realized that was this kids name . My boyfriend thinks I'm being crazy and that I shouldn't worry about it but i feel like im stealing her name, & that my dad and step mother are going to be upset about it .. we told our the family members we aren't telling anyone the name mainly becuase my dad was being an ass and was shooting down ever name we liked in the beginning. I dont know what to do btw my daughters name is Lexie . Lexie and Oliver. Lexie and Carsen.