Definitely! The Hajime no Ippo manga has a compelling plot with lots of exciting boxing matches and emotional character arcs. The way it portrays the sport and the growth of the main character makes it really enjoyable.
Ippo's age in the manga changes as the plot progresses. At the beginning, he's around 16 or 17 years old. As the story continues, he gets older with each new arc.
Yes, there are quite a few. You can find them on various fanfiction websites. Some might focus on his growth as a player from a female character's perspective, showing how she witnesses his development in the sport.
One idea could be a crossover where Naruto characters learn boxing from the characters in Hajime no Ippo. For example, Naruto might be intrigued by the discipline and physical training involved in boxing and want to incorporate it into his ninja training. It could lead to some interesting sparring scenes between the two groups of characters.
One idea could be a crossover with 'Dragon Ball'. Ippo could train with Goku and learn some of his ki - based techniques. This would not only make Ippo stronger in the boxing ring but also introduce a new element to his fighting style.