I can't decide what I want to be when I grow up. Which path should I choose?

Depends, as an actor you might have a chance at becoming extremely famous and in alright to amazing shape. Or if you want to join the SEALS, be in top physical condition, and have slight chance at fame, but thats only if you qualify and get through training.

Movie Star .

Face it: You will neither be a Movie Star nor a Navy SEAL when you grow up. Your chances at both are so incredibly small that both of these options are pretty stupid as permanent goals.
Pick a job that actually offers you chances of employment and does not end in either chronical depression or the chance of being shot in the head by some pissed of muslims.

What ScHall said, but in more of a "you's trollin'?" kind of tone.

If you just want to know what the ideal thing you would like if you could do anything in the world is, then out of those two movie star is a better option. Frankly, managing hedge funds or management consultancy are the best careers if you can pick anything at all though.

In terms of what you should do in real life, you have no realistic chance of becoming a famous movie star, and when you fail the fall back position is unemployment, same as 95% of the other people who went through life aspiring to be actors. With the navy you at least have a job after you fail the selection process for SEAL.

movie star blatantly, navy seals you'll be working all the time, movie stars work when they want, on what they want

If you aim to be a SEAL, you'd best get off your ass and start reaching physical peak, like right now.

During HELL week, they eat 7000+ calories a day and still lose weight.

Movie star. I think they earn more money depending on the frequency of films/shows they act in.

But there are rather slim chances of actually getting somewhere worth while

Of the two a Navy SEAL.

you should be the next james bond