I can also conclude that I am at rest. I don't understand why this is so hard for you to understand. Read a little into General and Special Relativity if you don't believe me.
Please explain how you're able to come to that conclusion, and don't just say it's because of the equivalence principle. Tell me exactly what about the equivalence principle and special relativity can lead you to this conclusion.
Another way of stating the equivalence principle is that gravitational acceleration is indistinguishable from other forms of acceleration. According to this view a student in a closed room could not tell the difference between experiencing the gravitational pull of the earth at the earth's surface and being in a rocketship in space accelerating with a = 9.8 m/s2.
EXPERIENCING the two accelerations is indistinguishable. This does not at all imply that if you see someone accelerating, you wouldn't be able to tell if it was that person or yourself who was actually accelerating.
Drawing equivalence between two frames of reference is only possible if:
1) One frame is experienced/perceived and you're equating that frame with another one that you could be experiencing/perceiving.
2) You're observing an external frame of reference, and you're equating that frame with another external frame of reference.