Just say, 'I try to be' or 'it's just one of my good points'

Hello Nydia, In this context the person seems to mean it that " you are modest", because obviously he notices that your English not 'so so' as you say. So in this case you either tell the person concretely why you think your English is only 'so so' ,for example by pointing out that your spoken English is not as good as your written and that is what you have to improve.You could say: You should hear me speaking , it is not really that good ".

Hi say just "Thank you" because it is a compliment or if you're not sure it is a joke or not "but my French is better..."

"yes i am"!!

I think "you are too modest" is a chinglish expression, Am I right?