No, you won't have to. Similar to many other Donut Games, the 50 new levels are designed as separate challenges. If you beat a level, you get 1-3 stars depending on your final score. If you lose or you want to improve an old score, you can retry the level at anytime.
Most Donut Games go free at some point. I have 18 Donut Games and I bought 7 of them. The others went free at one time or another. Benefits of TA addiction.