Feeling disappointed

I’ve been working out daily for almost 4 weeks now and have completely changed my diet. I went from drinking 2 20 oz bottles of Cola a day and snacking on Doritos, eating frozen pizza for lunch, lots of pasta, etc. I cut literally all of that out. I snack on mixed nuts, yogurt, or kale chips occasionally instead and with smaller portions than I used to. I’ve had 4 kids so my stomach sticks out a little more than I’d like but I do not think I have ab separation. I’ve been really focusing on core strength but I do work on the rest of my body and not strictly core so I can burn fat. I haven’t noticed any difference when I do comparison photos and I’m just feeling really disappointed. Does it typically take this long to see results? (Also adding that I’m 30 and 5’4 and weigh 122 lbs just in case that may be relevant information.)

*update 6 days later: finally seeing progress!! Thanks to everyone’s advice!! 😁