A tree is an expensive investment paid with years of time. You need to understand that a tree from seed is much more expensive than buying one on the nursery. You pay for exclusivity, but you will have a big tree that may bear decent fruit or not. Most probably not top-quality fruit, and most probably with vicious eye-poking thorns. If the garden is not very big, a smaller thornless tree could be much more convenient. Don't wait 30 years to discover this.
If your citrus species is sensible to citrus tristeza virus you may prefer to replace your tree or graft it on a tolerant rootstock. Orange trees over sour orange rootstock (= most of the orange trees planted before 1980's) have the virus. Lemons are tolerant, and its roots don't have this problem. Oranges may die after you have invested 15 or 20 years of your life on this tree.
Grafted fruit trees are vastly superior. You will want seedless oranges, so just do yourself a favor, buy a good navel type orange, grafted on the best rootstock available for your soil type, and avoid the rest of your life spitting seeds from your orange juice.
If replacing your tree is not on the table, you may want to graft yours. Extra point if you made a double or triple graft for enjoying different types of citrus fruits in the same tree. In this case Is essential to assure to buy virus free material before to graft other citrus tree with it.
Never, ever, use the same tool to prune older and young different citrus trees without disinfecting it each time you move to a different tree.