At 4 weeks one 1 my hormone level was only 42 which was picked up by a pregnancy test and a blood test. Its not too early to find out since anything above 5 on a blood test is considered pregnant and some pregnancy tests can detect a level as early as 12. Congrats on your pregnancy! :)
I had my positive at 3 1/2 weeks preg... Tests are very sensitive these days
Because the numbers are only a guideline, you can't use them to accuratly tell how far along you are. If you are indeed 4 1/2 weeks though, that's not too early to get a positive. Tests are sensitive enough to pick up an hCG of 20, and yours is far above that.
The home tests are pretty sensitive and pick up like over 20 hcg I believe