It is not true that children want to go to school better in the future and learn knowledge well in class.
Moreover, it's only the third grade. Personally, I think it's too early to learn olympiad, and I'm afraid I'll learn olympiad in advance if I don't learn the basic knowledge well, which will confuse my children.
My son, I didn't let him go to cram school or anything that morning, but his grades will be really poor in the fourth grade. Why don't you go after your friend introduced you? New king card? After attending a small class, you can see the effect in one semester, mainly because the ancient teachers there are more attentive and spend time helping my children before and after class.