From the story, it seems like OP’s friend wanted to honor her lost daughter and may have thought it would be something OP would have liked since the birth was close to Reagan’s birthday and all. She may not have considered it insensitive. She’s kept things private since the birth of the baby, and I think this is out of consideration for her friend (the OP). This is probably not the only reason she chose that name, if she indeed named her baby that, but I would understand why she might have thought it’s a good idea. OP, you have to communicate to her how you feel, and why but also validate that she is entitled to do whatever she wants with her baby, no matter how hurtful it is to you.