Continuation of existing curved edges to close mesh body I’m totally new to blender; this may be a really obvious question! I just wondered if anybody can help.
I created this mesh body
I then smoothed the vertical edge vertices.This had the desired effect of smoothing the curves, but shortened the overall length of the vertex edges. This has left the top and bottom of my mesh open.
I would like to close both ends of the mesh using a continuation of the smooth curved edge vertices.
As shown below: the open end(circled red) is where I’d like to continue the edge vertices(yellow) to a closed point or small flat face. I need the continuation to follow the smooth curve/angle of the existing edge vertices

Any help or suggestions of a way to do this would be much appreciated, many thanks.
Select the top edge which you want to extend, hit G twice to activate Edge Slide mode. Now hold the Alt key and you can move the vertices outwards along the projected edges. As soon as your vertices are close enough together press LMB or Return to apply the transformation. Now close the top by hitting F to fill it or  M to merge the vertices. But this extends the edges linear, it doesn't preserve the curvature.