Im very much in the same boat as yourself except me and my partner have been continually dating and seeing each other for iver 8months now, we do everything together, both families love each other we have taken long weekend breaks together, gone away together literally everytbing you do as a couple weve done, even the ****ty arguments.
Im very much like yoirself, i believe in knowing where you stand, in todays generation its all to easy for someone just to turn round and be like "but were just friends".. that doesnt wash with me.. however whenever ive brought up making it "official" with my significant other if anything its pushed her away, it puts the pressure on of actually being in a relationship even though the way you are with each other would signify a relationship anyway. I decided to take my own moms advice and not worry about putting a stamp on it.. things happen naturally.. going back to the 50s 60s 70s onwards etc there was no stages of relationships... it seems today theres so many dofferent parts.
Part A - The txting part
Part B - The seeing each otherr/Dating part
Part C - The being together part..
Its all to much, i best sum it up with my ex... we were very much like you are now and when i got round to aaking her out her reply was " i thought i was yoirs allready"... that sealed the day and we were together 3years, and probably still would be had i not turned into a prick.
Relax is what im saying let the way things are ride out, before you know it if things are meant to be youll be married and have kids and you will have never asked the question at all. I hope everythings works out for you both my friend!