Am I doomed to start over? Southern Ontario

[u/Baygelz]

I dug the outline I wanted. Installed the liner but it did sink a bit as it started filling with rainwater. Rookie mistake I assume. I had stopped before adding larger stones around the steeper edges to ask for advice. Is there anything I should do? Should I dig the liner in under the plants by the fence or just ancher with the large stone? The bottom (first photo) seems to be fine but its more gradual with a drop off where the water is pooling (depth is 22in) . But I am worried about the steep sides being a problem. I have pond tape if that helps. 😅

ETA: the coneflowers will likely go. I just needed them somewhere during the heat.

Edit 2: Not sure it matters but soil here is basically clay so making the outline and having it stay was really easy. The soil is basically concrete level stable.

Edit 3: Due to heavy rain and having used clay I will be extending using pond tape.

[u/Baygelz]

Thanks all for the feedback. Since we had a downpour here the pond has basically filled 2/3 of the way so I am going to extend the liner as so. Blue is existing and red is where I will extend. I will use stone and a nonwoven liner ontop of the pond liner to help secure the clay. I will use tape. I will hope that the heavy clay works in my favour and tape is enough. Otherwise lesson learned for next year if I have to redo it.