hello, can you help me with my english, i speak spanish
A) who's taller, Mr Allen or his brother?
Mr Allen is taller than his brother

b) i remember the day i first met you

Is this ok?

Those sentences are both correct. In English we always capitilise "I" when we're talking about ourselves, otherwise everything there is fine!

If you'd like to practice any more English, take a look at the lessons on my profile :)