Starting to Build a Core While Overweight

Hello everyone,

I have been working hard at progressing in my horseback riding but something that is really holding me back is my lack of core. My coach told me I need to really up my core to help with my body control and my stamina. I am also not in denial, I need to lose weight and she is trying to help me get on track with eating.

A lot of the exercises I have looked up I cannot do (or not well/long) and I am guessing it is a core thing but my weight doesn't help.

Plank (I can only hold it 20 seconds on my elbows)....
Side Plank (nope)
Side Plank with hip dips (nope)
Crunchs (I can do these)
Leg Bicycle (very hard)
Leg Lifts (very hard)
Bed/Dead bug? (very hard)

I would love suggestions on beginning exercises that I can use to build my way up. Should I just keep trying to extend my plank and do crunches? Any tips or advice are welcome.

TL;DR' Is it possible to build a strong core while overweight? What are some beginner core exercises or variations that I can use to build up to the harder stuff?

Thank you so much!

by Jeshi via Bodybuilding.com Forums - Female Bodybuilding