At least you will improve your patience and focus, that's the minimum what trying to stay with the breath does. This kind of concentration brings some calm and relaxation because you stop churning your anxious or unpleasant thoughts for a while.
Other benefits I've observed during the last years are:
– the increased ability to "step back" and disengage from some overwhelming emotions or obsessive thoughts (I had strong obsessions before, not anymore);
– automatically becoming mindful and making your breath more comfortable in stressful situations (helps your body to relax because the stress causes strained breath);
– being able to catch "subtle" thoughts flying through the mind without verbalization, kind of peek into your subconscious processes;
– some long-forgotten memories coming up.
Basically, meditation is looking at your mind and getting to know it better day by day. Focusing on the breath creates a "still spot" from where you can observe all its movements without being carried away by them because you have your breath as an anchor.
Start with 7-15 minutes daily, see if you can push it further without straining yourself too much. Guided meditation is everywhere now, I recommend this one for a start: https://www.dhammatalks.org/mp3_guidedMed_index.html
"Headspace" is ok too but it's more commercialized with all the theme-based courses. But avoid the "accept everything, just be here now" Western McMindfulness – it's a waste of time, the mind should be more proactive during the meditation (see the attached book for some theory).