Hi. I'm 16, and this summer I’m pretty sure I’m doing a 6-week summer exchange program. I know I want to go to North America, but I’m not sure what country to go to. I have to have 3 choices, and these are the countries I have to choose from...

Canada
Mexico
Costa Rica

I know my 1st choice is going to be Canada, and I'm not sure about the 2nd or 3rd choice
I was thinking maybe Mexico as a 2nd choice, then Costa Rica or Cuba as 3rd

Can someone who has traveled to these countries give me some advice?
I'm a 16-year-old girl, and I speak a little French (very little)
I want somewhere that I would have fun, and would give me a good experience

Thanks a lot!

These all places are awesome which are mentioned in your post, but I would like to recommend you to visit Virginia. In current season its temperature is approximately 28 °C to 31 °C which is best for summer holidays. There are lots of places over there especially Luray, VA.
Moreover, Luray zoo, Luray Antique and Design Center, Shenandoah Caverns, Rancho Viejo and Artisans Grills, Shenandoah National Park are the main tourist attraction. So visit there and make your tour memorable.

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These all places are awesome which are mentioned in your post, but I would like to recommend you to visit Virginia. In current season its temperature is approximately 28 °C to 31 °C which is best for summer holidays. There are lots of places over there especially Luray, VA.