I think that the only negative result of having an agreed flag against your name is the inability to be promoted to TL3 within a certain time period, and I don’t think that counts if the flag is yours, but one of the @tech-advocates will be able to check the code and confirm (or not).
Looking at the spec file it does appear that a user flagging their own post counts against them, if the flag is agreed with. Moderators can ignore or disagree with the flag to ensure it doesn’t count against the user. Personally I use ignore, as the flags intent is usually to get the moderator’s attention, not “flag” bad content, and thus there’s nothing to disagree with.