As of today, January 26, 2020, there is no possible way to get CMMC certified; no way to get a CMMC audit. The CMMC Accreditation Body (CMMC-AB https://www.cmmcab.org/) has not created nor released the requirements or training for audit firms to begin the certification process. Beware of shady firms saying they can perform the audit now. Or worse, perform the audit now and then once the rules are released, immediately issue the certification. The CMMC-AB is building the C3PAO accreditation process with formal adoption and approval by the CMMC AB in the coming months.  No C3PAOs are yet formally designated nor accredited by the CMMC-AB.

What you can do is get ready for the certification by performing readiness assessments against the most recent CMMC standards, currently draft v0.7. https://www.acq.osd.mil/cmmc/index.html

It is expected that RFP's in Sept 2020 will indicate what CMMC level will be required for bid. With the amount of time it will take to become compliant, never-mind that NIST 800-171 was required back in 2017, there is no time to wait. Get compliant today and certified as soon as the board releases the information for creating C3PAOs.