Using expired film is something I do every day. Here are some tips on different types of film, and a general idea of what to expect.

Film lasts longer if refrigerated or frozen. If you don't plan on using it quickly throw it in the freezer. Store everything else in the fridge if you are able.

Below are *my experiences* with working with many different types, and brands of film. The time ranges given are in years past the expiration date.

1) COLOR PRINT FILM (C41) 5-9 years. (lasts pretty long)
a. if not stored properly you can experience faded color or slight color shifting. Expired color film is fairly stable, but will not be perfect.

2) BLACK AND WHITE FILM 10+ years. (lasts the longest)
a. if not stored properly you can experience fogging, and fading which appears as the overall image being lighter or whiter than expected and or blotchy white patches throughout the image. Expired black and white film is very stable, and if stored correctly will be near perfect.

3) COLOR SLIDE FILM (E6) 1-5 years. (goes bad quickest)
a. if not stored properly you can experience significant color shifting to the point where it will appear that the whole frame is tinted a particular color, usually PURPLE, BLUE, or GREEN depending on the manufacturer, and how the film was stored. Expired color slide film goes bad the quickest and has more problems than other types ... I use this type of film after expired experimentally only.

All that said I have shot film even beyond the years given above with decent results.

The previous advice of 'Don't use it on anything important' is good advice. Use it for something fun or casual. Don't run to a money making shoot with only expired film, you will be disappointed.

Don't expect perfect results. If you are using film you probably have already embraced this.

Without the box you can expect when it was purchased it has a shelf of 2-5 years (within expiration). You also mentioned that you thought it may be 2-3 years old, so it might still be within expiration.

Assuming that you aren't using this for a business shoot or anything critical;
Personally I would shoot black and white or color print film (C41) that was 2-3 years past expiration (stored at room temperature) without a thought. If the film was color slide film (E6) I would set my expectations lower, and use it as a fun experiment.