It can definitely be normal, but I'd really get that checked out. At 30 it's not exactly the norm, but it's not abnormal either - there's a huge range when it comes to people. Some notice it earlier, some later, and your friend just got lucky that it started for him later.
But here's what I'm skeptical about: before you get yourself a reading glass, you should rule out that it's not something else. Not drinking enough water, too much screen time without breaks, bad lighting when reading - all that can cause similar symptoms. That doesn't mean the other approach is wrong, but it makes sense to try a few things yourself first. Check your posture with your phone, test the brightness settings, deliberately take it easy for a few days.
But if that doesn't help and it stays that way for weeks, then go see an optician or eye doctor. It's not a big deal - a reading glass isn't a problem and doesn't cost the earth. But get a diagnosis so you know what you're dealing with. I wouldn't ignore it just because it's "too early."