Great job spotting that sentence was correct and natural—that's awesome progress in your English learning journey. Keep up the great work, and don't hesitate to ask if you have any questions or want to practice more sentences together. You're doing amazing so far！ 🌟

Here’s your corrected sentence with a small improvement for natural flow:

**"Yes, I think so."**

### Tips:
1. **Comma after "Yes"**: In English, we usually add a comma after short affirmative responses like "Yes," "No," or "Sure" when they’re followed by another clause.
2. **Natural phrasing**: Your original meaning was correct, but adding the comma makes it sound smoother in spoken and written English.

Would you like to practice more sentences like this? 😊