Your sentence is good and understandable!

However, there is a little correction. It should be: «Я намагаюся читати українську, бо я вчу цю мову».

You've chosen the ending correctly: -ю. This is the correct ending.

But намагатися is not a usual word. It has a part -ся. This part comes after ending:

• я намагаюся 'I'm trying',
• ти намагаєшся 'you're trying' (informal),
• вона намагається 'she is trying',
• ми намагаємося 'we are trying',
• ви намагаєтеся 'you are trying',
• вони намага́ються 'they are trying'.

So, don't replace «ся» with «ю». Instead, replace the ending «-єть» with «-ю», and add «ся» after it.

«Ся» means that the action is directed at the speaker. The original meaning of намагатися 'to try' was 'to strain oneself', like «я намагаются читати» = 'I'm straining myself to read', and «ся» corresponds to 'myself'. So, it's not really the ending of the verb. It's attached after the ending.