Will I have trouble saying I love you?

It feels awkward because you are not used to hearing it but you'll overcome that in no time. As for it being hard to say, my only advice, say it when you truly feel it with your heart, your soul and every cell in your body. Don't just throw it around, or say it in return because you feel like you must to please someone. Every one of those words must be believed in.

I wouldn't worry about it too much. There are plenty of ways to express your love without saying "I love you". Also, guys usually don't notice what you're NOT saying, but rather what you ARE saying.
If a guy can't accept you for a simple thing like that, you probably don't want him anyway. Focus on finding the perfect guy first, and don't rush things!