Maria,
Since Portugal is part of the EU, you will also need to comply with the children's safety regulations of the EU. Great Britain, The United States, Canada and Australia all have children's safety regulations. These aren't suggestions, they are mandatory laws for all sellers of children's products.
If you want to sell around the world you have to 1. comply with the EU laws, and 2, comply with any differences that each Country may have. Generally they are quite similar
Yes, you may sign up for the USA CPSIA small batch manufacturer exemptions. If you do, you may take advantage of the exemptions. It's free and easy to do. That will help you sell your products in the United States.