Situations where it's likely childish:
* Anonymous: An anonymous note is often perceived as creepy or immature, regardless of the compliment's content.
* Overly effusive or romantic: A note filled with exaggerated praise or declarations of love from a stranger is inappropriate and potentially unsettling.
* Grammatically incorrect or poorly written: This suggests a lack of effort and maturity.
* If it's delivered in a way that could be considered stalking or harassing: Leaving notes repeatedly, or placing them in private locations, crosses the line into harassment.
* If you don't know her: Complimenting a complete stranger via a note is generally seen as awkward and potentially intrusive.
Situations where it might be acceptable (but still risky):
* You know her slightly and it's a genuine, brief, and polite compliment: For example, if you're in the same class and you genuinely admire her work on a project, a short, simple note saying something like, "I really liked your presentation on X topic," could be acceptable. Even then, it's a low-probability high-risk strategy.
* You're part of a club or group together: Within a shared social context, a positive comment might be seen less negatively. However, still keep it brief and professional.
Better Alternatives:
In almost every scenario, a direct, in-person compliment is better. If you're too nervous to speak to her directly, consider a short, casual conversation that gives you an opportunity to compliment her in person.
In short: Writing a note to compliment a college girl is generally a risky move that is more likely to be perceived as childish or creepy than charming. Direct communication is almost always a better approach.