Six-year Old Lost Second Molar???

My son just lost his upper left second baby molar today (he just turned 6 in February!!) He never experienced any pain until it came out all at once today. I looked at the tooth, it looks "normal" - hollow in the middle like all his other baby teeth have been, the gum is nice and pink/red, doesn't look infected at all, and I couldn't see any holes through the tooth anywhere. It looks like a regular lost baby tooth... but it's a molar and he's only six!!! Is there a way to tell whether this tooth was "supposed" to come out or was it decay? He never experienced any pain (until today, when it came out) and he only had a check-up back in December where the dentist found five very tiny cavities that weren't urgent to fill.

My son has always had very strange, and very early, tooth eruption patterns. He was born teething and had all his primary teeth by the time he was 15 months old (save for one very late lateral incisor that didn't come in until he was nearly three). His first 8 primary teeth were, in order, two front bottom, two front top, all four first-year molars at once (about 5 months old). He lost his two bottom front incisors at 4.5 and 4.75 years old. By the time he turned six in February he had 10 permanent teeth: the four across the top, two front incisors on the bottom and his four six-year molars. So he's had some pretty unusual teeth eruption patterns and obviously very early for growing teeth. But still... six years old for his first molar?? Is that reasonable even given his weird tooth history?

K.

Additional info: he has a dentist appointment on May 3rd. I'm trying to decide if we need to go in before that. Our dental insurance doesn't start until May 1st, so any visit before then would be out-of-pocket. I can't see that there is anything a dentist could do about it now, and putting in a space-maintainer could wait four weeks, couldn't it???

Additional info: I only listed the first 8 primary teeth because I couldn't remember when the other teeth came in :) I remember them well because they were unusual in order of eruption (central incisors, then molars, THEN lateral incisors) and how soon his first molars erupted (five months old). He had 19 primary teeth by the time he was 15 months old - all the primary teeth (including second-year molars) except for the upper left lateral incisor which didn't come in until he was nearly three. He started losing baby teeth at 4.5 years old and over that first year lost and replaced the two upper front incisors all four lower incisors. His six-year molars came in AFTER he already had six permanent teeth. So I'm used to him being unusual! But losing a second-year molar next?? Seems too unusual, even for him. Is it possible that the incoming six-year molar pushed it out prematurely??