I think I'd be okay with this series if it were just shoujo or if the age differences and such weren't all over the place. It's a nice idea, but what would be a great heart-warming slice-of-life series is ruined by the shounen-ai aspect.
Contrary to what others have said, I think there's plenty of evidence that the author isn't at all bothered pairing underaged characters with older characters.
First there's Tomo who declared his love to sensei and announced to the others that he would marry sensei. This did give me pause, but I thought maybe I was too quick to judge so I continued reading. Later, we see a flashback to Yuki's past as a child where he's smitten with his sensei and even kisses him and persists in wanting to marry him, only giving up not long before sensei dies. Then there's Nora who supposedly isn't much older than Yuki although he clearly looks much older than Yuki and does mistake Yuki for a girl and nearly rapes him. I'm kind of surprised this part didn't seem to bother anyone else - yes, Nora doesn't go through with it upon finding out Yuki's a castrated male, but Yuki clearly didn't want Nora to push him down and pull off his clothes! I finished that storyline just to see what happened with sensei and the neighbor, but that's where I had to stop. The story was fine, for the most part but the shounen ai bordering on near-shotacon was so not my thing. If you feel this also might bother you, then I recommend giving this one a miss and just reading Natsume Yuujinchou or some other feel-good series.
Another issue I have involves Yuki. He's basically treated as a woman and is drawn with very full lips as an adult (lips that were NOTHING like his lips as a boy or older teen!). Then he calls himself sexless because he was castrated. I'm sorry, but really? He's castrated so he has to grow up to look just like a woman and that's why he's always mistaken for a woman a lot 😕 No. Just, no. First of all, castration does not magically turn a creature into something sexless and secondly it doesn't really make them look like females! It seems more like a really bad excuse to me and I have to admit it bothered me the entire time. I don't mind castrated or asexual characters, but when they're treated like this it just feels very, very wrong.
That said, if the things I mentioned don't bother you, then feel free to give this a go. Like I said, there are some good aspects to the story, but for me it was a let down. I think it was even more disappointing for me because I read the reviews on here and expected a nice story with very mild shounen-ai when in fact it felt like every other shounen-ai from the late 90's through early 2000's where you have a cast of almost all guys and repeated "hints" that are too blatant to be anything else.