It doesn't matter what you told the officer dude. You weren't recording the conversation and he didn't have to write it in his notes and probably didn't. All he would have written was how fast he said you were going and maybe something about you lying to him or displaying a bad attitude.
I know you were right next to an 18 wheeler and were trying to do the safest thing, but in most instances, that doesn't matter to a cop or a judge. And I hate to say this, but it's true, the fact that you're young, black, and have a pretty impressive prior is not going to help either. The cop was most likely making his impressions of you based on profiling, and giving him a BS answer like you were looking at your speedometer when you knew you were speeding probably didn't help. The isn't concerned with what any motorist on the street is doing except YOU, unless you can prove they put you in a position where it was impossible for you to avoid having a problem (ie, being rear ended or being run off the road - you can't get a left of center violation or reckless operation charge if you are run off the road).
It's also likely that the judge is going to look at your prior and feel like you got off way too easy for doing 100+ on any road and want to punish you more severely this time since they will perceive you did not learn your lesson after being given a break.
The short story behind all this is - you need a lawyer.
You can try deferring the trial date until after your probation, but it probably won't matter because if the judge wants to get you, she'll get you because the offense took place during your probation. Trial date is irrelevant and will only help if your attorney has a good relationship with either the prosecuting attorney or the judge.
But this is why you need an attorney. Most likely, the prosecuting attorney will not take you seriously if you can find the time to figure out how to represent yourself and you will not be able to get a good deal. On the other hand, if you find an attorney who has a good relationship with the prosecuting attorney and the judge (and who is also very intelligent and legally savvy), he will be much more likely to be able to make a deal.
Criminal convictions can make life unnecessarily hard on you, especially when it's for something BS like speeding. No company asks you why you got a misdemeanor or felony, they just ask if you got one. The background checks they perform will typically not give them an incredible level of detail about what exactly happened to you... it will just give you the charges. Most employers who see a criminal misdemeanor are not going to assume you were speeding, they'll probably assume assault, robbery, or something like that.
Again I say, you need a lawyer.
BTW, how did you get such a late court date? Did you waive your right to a speedy trial? Technically you're supposed to have one within 30 days unless you submit a motion to waive that right, and if you didn't do that, your attorney may be able to argue your Constitutional right to have a speedy trial was violated making the case moot.
Also, were you arrested? And are you scheduled to be arraigned? Both of those are important points.