1) We've been dating for five years, so we decided we should just go all in with our relationships. 2) It's been 5 years since we started dating, so we decided we should just go all in with our relationships. 3) Now that we've been dating for five years, so we decided we should just go all in with our relationships. Could you please tell me which sentence is more natural among 1), 2) and 3)? I want to know the usage of "now that" and "since" Could you please help me? Thank you so much.