Hiya Picasso and welcome to ThePhotoForum.
Congratulations on getting (and successfully using) your first SLR.
You got the idea of DOF (depth of field) right, it shows.
You used the on-camera flash on the first of your two flower pics, I gather? It makes the flower a bit flat in appearance now... do you also use some kind of post processing software to mildly adjust your once scanned-in pics a little? That first could do with some darkening... only a bit.
The second is nice, you captured the red very well... it is hard to get red flowers right, you know!
In the course of time you will hear more and more people tell you about "too centred subjects" in the frame ... and maybe you will find out for yourself that after a while you begin to find your own pics with flowers smack in the middle of the frame a little boring ... this is so because our eyes/brain like pics to be a bit off-centre. So a subject - even though best focused when it is in the very centre of your viewfinder - should always be somewhere off centre. Imagine you'd put a grid of thirds over your frames, horizontal thirds and vertical thirds. Subjects are best placed on the imaginary cross lines of those thirds, either to the upper or lower right or upper or lower left. That is called "The Rule of Thirds".