There are people on SSDI earning a lot more than that without it having any impact on their CDR.

Unless the people who have hired you as a babysitter are reporting this income to the IRS, I would seriously consider not even mentioning it to the SSA, if I were you. But that's just me.

If you do report it, two factors will protect you from having an adverse impact on your benefits. #1) The babysitting job is not as demanding as other employment would be and so is doable by you, even with your disability. #2) You don't have the ability to work full-time as a babysitter earning the minimum wage.