How can you be sure?

Over the past few days, I resigned to accepting my minimum wage job for the summer. I literally wipe shit from babies' cracks, but it pays the bills, has good hours, and is free birth control.

I had accepted my fate for this summer. Until today. I got an email from my number 1 internship pick. During class. During a discussion on birthing children. They want to interview me! I wanted to scream, and contemplated telling the random chick next to me about my news since I could not hold it inside any longer, but instead, I grouptexted my family. Oh, technology.

After thinking more about it, I found myself feeling sad. I won't be with my family. I may be out of the country. What if it's a terrible internship? What if it's just legal slave labor? What about seeing my boyfriend? Could we both handle being (literally) an ocean away?

Then the feminist inside me slapped me across the face.

Anyway, I still have questions. What if I don't make the right decision? Say I get this internship and it's in London or Washington D.C. I can hardly pass up a reason to go to either place, especially London. I'll miss the last summer that my family has all together at home. I won't be able to do the Color Run with one of my best friends. What about all those Pinterest recipes and crafts?

Finally, my question is:

How can you be absolutely, confidently sure you are making the right decision in any situation?