It’s nice to hear about your love of tattoos! It sounds like you’re thinking about a meaningful method to share that love with your girls. Your oldest is interested in space and aspires to be an astronaut, so a space-themed tattoo could be a great choice.
You might consider designs such as stars, planets, or perhaps a miniature rocket. It may be a great bonding activity to get matching tattoos or something that represents her ambitions. Whatever you pick, there will undoubtedly be a particular bond between you and your girls. Happy tattoo planning!