Would this be a problem later down the line?

Alright so i’ve been dating my bf for almost three months now. Things are going great but i’m a little bothered by something. Ik his ex is completely in the past but i just wanna see if anyone has experience with this...... he dated her for four years.... they knew each other since 8th grade and dated the four years of college together, probably having tons of fun. They had tons of things in common, video games, favorite junk foods, did band together, had all mutual friends together.

It’s scary to me because him and i work well together but we are not that similar. We have 0 mutual friends. No one in his life knows who i am (they know he has a girlfriend). We both don’t have social media so technically it’s not official to others which is fine for me bc i’m very private but also at the same time i feel like making it facebook official is kinda good cuz it lets people know? His ex has no idea he has a girlfriend now.

But anyways, does anyone have anything similar they went through? I really do like him but sometimes this concerns me a little bit.