No.

There is absolutely nothing about this issue that relates to birthdate being mid-year.You might be thinking of the old rule, which still used "year you turn 70 1/2" and not by birthdate.

Everything is based on Tax Year. Her actions in 2026 are actions in her 73rd Year. It doesn't matter when in this year she takes these actions or the date of her birth. They're all part of 2026.

RMDs begin this year, because she turns 73 (for those born 1951–1959) this year. It is changed to 75 for those born 1960 or later. She can take her RMD any time in 2026 or over time in 2026. The deadline for the first RMD is April 1 of the following year: 2027 for her first RMD year, but then she'll need to take two RMDs in 2027 if she waits, because subsequent RMDs must be taken by Dec. 31 annually.

She can convert (not roll) Traditional IRA funds to Roth IRA funds. If she doesn't have any basis in the Trad IRA, then the amount converted is reported as taxable ordinary income on her Form 1040 for the 2026 tax year.

Conversions will reduce the Trad IRA account balance for purposes of RMD. They don't replace the RMD. They won't eliminate her first RMD, because the RMD is calculated on the fair market value (FMV) of the IRA as of December 31 of the previous year. Even if she stalls until April 1, 2027, it uses the Dec 31, 2025 ending value.