I am new to blender and 3D modeling as well. My model seems to be fine when viewing it in edit mode, but in object mode, a edge that shouldn’t be there appears and when i preview the rendering, the model is very different with new faces appearing that do not look anything like the model. Any help would be appreciated.
The renderer can only render triangles, therefore when you have non triangles on your model they are triangulated at render time. You have a face that looks to have seven sides. This can be triangulated in a number of different ways but blender cannot read your mind as to which formation of triangles you want.
You have better control if you model as quads and only use ngons (faces with >4 sides) on planar surfaces.
If you want to render flat shaded, without triangulation, turn on Auto Smooth in mesh properties, and turn the angle down to zero. But basically, yeah, what Richard said.
By the looks of it you would be better off starting the whole model again because this one is messy. Use separate objects or separate geometry for things that are separate, and don’t add or remove edges if you don’t know why you’re doing it. Currently there are a lot of n-gons, faces with more than 4 vertices/edges/sides, which will be a problem with further modeling and UV unwrapping.
As mentioned there are mesh problems
Include the whole interface in the screenshots when asking questions and include an example .blend. Not one or the other, both. Use the images to help you explain, and include the .blend for everyone else to help troubleshoot and use that to make images in their posts when they answer. Tutorial linked in my signature shows how and where.