How long is too long to make it official?

I been dating this guy for 4 months. We aren’t official yet. We spend most weekends together and some days during the week. I have asked a few times about being official and not just being exclusive. he states to me, not yet and he likes to take his time before making things official. I’m starting to get the idea that things won’t move forward. What’s too long? Or am I being impatient? My friends ask all the time what are we, and I’m not even sure what to tell them. I feel like we can still get to know each other while making it official. Thoughts please.