I've always been of the opinion that if you want to 'practice' (Hell, it's all practice to me!
) you may as well use good carbon steel to begin with. That way, if you get a really good grind you can practice your heat/quench. If that goes well you can practice your temper. If all's good so far, practice handling. Then you can practice your leatherwork.
You'd be pigged if you did a really nice, top quality, even & level grind in mild steel & then couldn't do any more with it! I'd rather make 10 useful-but-not-so-pretty knives than 1 stunning-but-useless blade.