WARNING! You will get diabetes. This is probably the most wholesome manga I have ever read. It starts of slow, like it's good but not that good, then after 10-20 chapters in, may god bless you, as your sugar intake goes off the roof.
Please give it some time. Also, the synopsis is wack, the mc is just an edgy chuunibyou. Also if you are wondering why the fuck the mc is so small he is probably 12 or 13 and also FBI may come in yours house, since the author has a tendency to show some "cultured" art about the female mc.