If you were charged with 22348(b), Speeding Over 100 MPH, the fine is $200 plus penalty assessments, so could be up to $900.
However, a more significant concern are the negligent operator points–2 points–that would be added to your DMV record. This can really do damage to your insurance, not just because of the points but also because of the way you got the points, if convicted of 22348b.
The potentially most significant issue is that your driver’s license will almost certainly be suspended for 30 days. If you continue to drive despite having a suspended license, and are pulled over for any valid reasons by police, they will cite you for driving on a suspended license, California Vehicle Code section 14601.1(a). Driving on a suspended license is most often issued as a misdemeanor, a criminal charge.
Note that driving on a suspended license, if convicted, is subject to a maximum of 6 months in jail, about $4000 in fines and fees. There is no minimum jail for a first offense, but there is a minimum of about $1300 in fines and fees. It is also priorable, meaning if you have had a similar charge before then you will might be subject to a minimum of 5 days in jail and about $2000 in fines and fees. In addition, 14601.1 is subject to 2 DMV points. If you are convicted of both 22348(b) and 14601.1(a), then your license would be suspended for an entire year. This would be due to having 4 DMV points within 12 months. This is a hypothetical but very possible situation, a domino effect of driving on a 30 days suspension.
On the other hand, it is possible, but unlikely, that an officer might cite someone for a lesser charge even if they caught someone going over 100 miles per hour. However, if they are going to do this, they usually write the ticket for 100 or 99 or 95 and cite it as 22349, exceeding 65 mph. CVC 22349 is only subject to one point and half the fine. Your license could still be suspended but a judge might suspend it shorter, like 10 or 15 days, if at all.
(If you hire an attorney, there are different ways they can protect your rights and driving privilege. I have had great success with these types of cases, from dismissals at arraignment, dismissals at the trial hearing, and reductions for lesser consequences. Although having watched plenty of pro pers–defendant representing self–fight this charge, I have never seen them achieve these better results.)