Hello Pond Pros,

I have been sitting on the porch looking at the back .25 acre that I have to mow religiously thinking to myself that spot would make a much better pond. I have been party to, labor for, and enjoyed many pond projects- so I have a basic understanding of the ins/outs...but would appreciate some planning assistance.
The spot I am looking at is approx .2 acre - 100ft x 100ft. The terrain is perfectly flat- and watershed is not on my list of concerns, this will be a small pond with water level management hopefully coming in the form of mother natures graces initially, with top-off from the well. I am torn on the size/shape to go with. Having been through many seepage/leak issues in the past- I am thinking of just doing a liner to keep it simple. My goals for this pond are swimming hole/bluegill/CC for my newborn son...so I have a few years of runway on the fish production.
The site looks like this:


I am fixed on the border, but can definitely be creative with shape/design/depth. Given that I am considering using a liner, I was also considering making the pond smaller or shaping it to optimize liner costs and minimize seams.

A few questions for the pros:
-Do you have a recommended depth for here in South Texas?
-Any thoughts/recommendations on liner shape/size
-What am I not thinking about ?

I thank you for your consideration and would love to hear your opinions on how you would approach this small pond project.

-Jeremy