Is this constipation?

Hi, my kid just turned 4MO. She's drinking Nan. On 23rd May (7th day since her prev), her poop was mushy green. On 30th, she had some poop on her butt, just at her anus. Today 1st June, she pooped but it looks semi solid or a lump . This is the first time it is like this. & she didnt cry while pooping. I didnt even know she pooped until morning diaper change. Usually she poops every 4 days. Should i be worried? Or monitor until her next poop?