没错！ 或者前面加上主语也可以： 我今年五十多岁了 他今年五十多岁了 口语中，回答别人问你今年多大了的时候 时间状语放在后面也ok： 五十多岁了，今年

That's a good question. BTW: 你应该用"跟",而不是"根".

I don't think many Chinese would say that in speech, though it doesn't sound awkward. Suppose I was 53 years old now, in answer to the question "你多大了?", I would say "我今年五十三(岁)了" or "我五十多(岁)了", rather than "我今年五十多岁了". "我今年五十多岁了" also makes sense, anyway.

同上

不会，这句话没有问题。“五十多岁”表示年龄，“今年”表示时间，完全正确。