Building muscle can be hard. While online it may look like everyone is perfectly sculpted, most of these people will have been training for years and years, so don't expect to have muscles like them in a few short weeks of exercise. It also requires you to really push yourself: if you've been lifting the same weight for weeks and weeks, you're doing it wrong.
Work with the principle of progressive overload, which means continuously adding more load to the muscles. As soon as a weight starts to feel easy to lift for your desired reps, you need to lift heavier. It can be as small as an extra 1.25kg, but every little helps.
It's also important to note that visible muscles aren't an indicator of overall health. Actually, women who have abs may be below the healthy body fat percentage for a women. Tick off your training, eat well, recover adequately, and the rest will follow.