No it’s not too late, you’re only 25, that’s pretty young. Yes other people have started dating much younger, but in the grand scheme of things it doesn’t matter much. Focusing on yourself and your career and education can be attractive to others, so don’t worry about having “wasted time” or anything. Losing weight if you’re overweight helps, same with gaining weight if you’re underweight. Just be sure that the primary focus is health and ignore all the unrealistic body standards in movies and on social media. You’re doing well to put yourself out there, don’t worry about your friends, I’m sure you’ll find someone single that wants to have a relationship soon. You seem to be on the right track, so don’t worry. Avoid all the weird dating advice on the internet, it’s not helpful.