Kallum Aish, then 17, was at the wheel of the Renault Clio when he lost control, hitting Patricia Faulkner and her Staffordshire bull terrier Millie on July 22 last year.
It happened in Doe Bank Lane, Great Barr, throwing the victim – who was left badly hurt – over a hedge.
CCTV footage of the crash was released in the aftermath by police as part of an appeal for information.
The footage showed the blue Renault losing control in a cloud of tyre smoke, then crossing the carriageway, hitting Ms Faulkner on the opposite side of the road, before disappearing into undergrowth.
Aish, who is now aged 18, was at Birmingham Crown Court after previously admitting six offences: causing serious injury by dangerous driving, criminal damage, failing to stop after a crash, driving while unlicensed, uninsured, and possession of cannabis.
He was due to be sentenced but his barrister Joseph Keating said some important details in the case now needed to be settled. Mr Keating said there were aggravating features to the case that Aish “was racing and there was excessive speed” at the time he crashed.
However, he said his client’s current instructions were currently “contrary” to those factors, and asked the court for an adjournment so Aish could iron out those issues with his legal team.
The judge, Mr Recorder Watson, told Aish his case was being adjourned until April 30 when he would either be sentenced or an administrative hearing would take place to set yet another new court date.
He said: “Kallum Aish, your case was listed today for sentence but on the basis of what you told the probation service and the discussions you had with Mr Keating, that’s not possible today.
“You have some important decisions to make.
“Those decisions must be made in the next week and the court is to be informed no later than 4pm on April 23, next Friday, as to whether you maintain your guilty plea or wish to advance a (different) basis of plea.
“Any basis of plea falling short of the prosecution’s case is likely to lead to court having to decide the issue, by way of evidence.
“That decision will be yours to make and I direct that it must be made by the 23rd of this month.
“If it isn’t, the hearing on April 30 is unlikely to go in any direction you’d like it to.”
Aish, of Finchley Road, Kingstanding, Birmingham, who has previously been warned by a judge to expect a sentence behind bars, was conditionally bailed to appear back at the city’s crown court at the end of the month.