I Saw A Dragon? Spirit Guide? Demon Entity?

When I was around the age of 6 I was quite mischevious and I sneaked out of bed and went down stairs. As I got to the living room door I pushed it open and there infrount of me was a dragon! It smelt like sulpher or smoke and I felt its energy and presence so strong that to this day I often wonder what it was I saw? The dragon filled the living room. It was curled up, facing away from me and its tail was wrapped around its body and I never saw its face as it looked as tho it was preening itself. I could hear the creature breathing, It was very deep slow strong grunting breaths. It was the classic looking dragon you see in films where the knight goes off to slay a dragon but it had green and bits of goldish brown. It had scales. It was to big to have fit threw the door and there were no windows in that room so no idea how it fit threw the door as I said before it filled the room. I didn't feel threatened I just froze for a minute took it all in and then backed away slowely! I lay in bed for a while and didn't hear a sound. By the time I got up in the morning it had gone and obviously when I told my mum she didn't believe me. Figment of my imagination etc. To this day that experience has stuck with me! Mainly because I didn't act differently. It knew I was there when I saw it. I could tell it sensed me. My bigest regret is backing up. If I'd had a second chance I'd have touched it. Spoke to it? Asked questions. So I'm living with regret of a missed oportunity and iv ever since been online trying to find out what I saw and I havnt had any luck apart from people claiming to have seen them in the sky but nothing like my experience. Reason for posting I want answers. What did I see? Why did I see it? What could it have wanted? And how do I find it again as I have questions for it. Any thoughts and theories welcome. I have experienced many more supernatural things altho this was the first and the biggest. I shall list my others another time. Thanks for reading