I am writing a novel that is in present tense. I'm worried I'm going back and forth from present to past tense when I describe the physical characteristics of people my main character meets. Here are a few passages as an example.
The sounds of feet trudging through the dense undergrowth grow nearer to my fortress. I freeze, all I can hear is my heart thumping in my ears. I bite down to stifle any involuntary sounds of fear and taste blood from my lip. As they get closer, I realize whoever it is must be coming into the house. I slowly sit up and begin to crawl toward the ajar doorway in the south. I can hear voices talking quietly. I climb out of the doorway and behind a wall, out of sight yet close enough to make out their conversation.
The men came around the corner, blades at the ready. When they spotted me, both their faces lightened slightly. The younger one appeared to be in his 20s, chestnut hair curling in the damp warmth of the morning. Dressed in a kilt of blue, green, and red with a white shirt more like a rag than something to be worn. He had a slender face with a strong jawline and high cheekbones. Although his expressions were guarded, a slight smile flashed along his lips, and I could see the pity in his bright blue eyes as he looked upon me in my rags. The older man was less attractive than his counterpart. Maybe they are father and son, I thought. His hair was also chestnut but peppered with gray. He had it tied up in a braid. Little pieces of it lose around his rather round face. His eyes were a similar shape to that of his doe-eyed partner, but they were filled with more wisdom. Instead of blue, they glowed amber in the morning light. His skin was tan compared to his light eyes. The younger man had a near perfect complexion, whereas this man had wrinkles and looked as if he carried the whole world on his back. This man’s facial expressions are much less guarded, and I see a look in his eyes I’m all too familiar with.
Forgive me for grammar errors, this is a first draft and I have never written before. I just want to be sure I am not screwing up my tenses.
Also, if I am changing tense, how do I adjust and describe them in present tense?