if you do things like commerce etc, u have alot of optiopns u can choose from. Given u satisy certain prerequsits (band watever in 2u maths etc) u can get into things like STAT171, ACCG100, ACST101, ECON111, ECON101, ACCG101, COMP115 etc in first yr even if you're not enrolled in Actuarial. Then if you're GPA is high enough, you can get into acst and wont need to redo these subjects. Only subjects you'd really miss are ACST151 and ACST211 if you plan very neatly. So only 2 extra subjects.
But really, 75% of ppl who make the 97uai+ cutoff drop out coz they cant handle actuarial. I'm giving you my opinion. Like right now, i reckon i might not make it through, even though im doing relatively ok. I think ppl who get say 90uai (not u, u'll get higher), transfer to actuarial, have a slim chance in the end, and waste all that time and effort.