Firstly just check you can get a first class medical then identify what areas of commercial flying you want to do? Airline or other.
If its Airline modular or not it will cost money.
My son was very focused and resisted all advice from his school to go to university.
He went through the modular route via Oxford and then applied to CTC who were closely associated with EasyJet.
He was selected and type rated on the 737 and very lucky that EasyJet took on 6 more young pilots through CTC in the recession.
He was one of those 6 and at the age of 20 was right seat on a 737.
The Engineering option at University sounds a good option as a back up but keep focused on what you want to do.
Pace