Yes, this seedling is an oak.

And considering how large it will soon become, it is also an unwanted plant.

Thanks.  That is good to know.  Can you give me an idea of how big it will be in, say, 10 years?  Do oaks grow much faster than evergreens?
Thanks again

While I am not a forester, I have worked as a tech on oak restoration projects. Oaks grow relatively slowly compared to evergreens. After 10 years grown in a sunny spot it will probably be 10-15 feet tall--much smaller than a similar aged Douglas-fir. However you need to keep in mind that oaks can live for literally hundreds of years and develop huge canopies. On an urban lot or in a home garden it might likely be undesirable because of its size and lifespan. On rural acreage far from buildings, electrical wires, etc. it could provide habitat for birds and wildlife, shade and beauty.

Please take at look at this OSU Extension Publication Selecting, Planting, and Caring for a New Tree for further insights on picking the right tree for your location.