Oralloy, there is no absolute
frame of refernce. You are confusing the word "inertial" with the term "absolute". It doesn't work that way. In one frame of reference, right now, you are moving at 99% of the speed of light. In another frame of reference, right now, you are not moving. They are both equally valid.
Your use of the "inertial frame of reference" complicates the picture because it brings in acceleration/deceleration. But it doesn't change the fact that each perspective is equally valid
In the case you suggest one person observes that you started at rest and then accelerated to "near light speed". However, don't forget, that there will be another frame of reference where an observer would observe that you started at "near light speed" and then decelerated to zero.
Even considering acceleration (and inertial frames) it is still equally valid to say you are, right now, moving at 99% of the speed of light-- and that you are moving at 0% of the speed of light. Right now, both of these are valid (in equally valid frames of reference).
While you are accelerating, you will experience the acceleration. However accelerating from rest, or decelerating from a fast speed to rest, are indistinguishable (since they are two ways of experiencing the same phenomenon from different points of view).
Once you stop accelerating, there are still multiple frames of equally valid frames of reference-- in one of them you are going 99% of the speed of light, and the other you are motionless.