It’s not a good idea to use a steel string guitar for classical lessons. The fretboard is curved and not nearly wide enough, plus the steel strings will just not generate the tone that classical music requires. If you like the one you have now, look into getting an inexpensive classical guitar.

yes you can use an acoustic guitar for classical. I have played the classical guitar for 5 years now but before then i used an acoustic guitar. It doesn’t really matter what you learn on for it will sound good no matter what type of guitar it is if it is played right. At one point i even used an electric guitar and that was fine.