oh!! Baš želim da posetim vetrovitu Hrvatsku uskoro!!!
^ Your Croatian is not bad, you're improving
(Učim hrvatski svako jutro (if you mean that you learn Croatian every morning), ali je vrlo težak - could be more correct don't worry, I know that learning of Croatian is hard for non-native speakers)
Želim ti lijepu subotu - when you're saying it to 1 person
Želim vam lijepu subotu - when you're saying it to more persons
Hvala, također
And "Oprostite zbog engleskog." could be more correct in this situation I've used zbog because it shows the reason (why sth. is like that, etc.) ... there are more words which can be used
Examples:
Ušla sam u dućan zato što trebam kupiti nešto. - I came into the shop because I need to buy something.
Nisam išla zbog njega. - I didn't go because of him.
etc.